λ, see Wavelength
ρ, see Acoustic density of medium
ω, see Angular frequency
AAH, see acoustic adaptation hypothesis
https://glossary.acousti.cloud/acceptance_song
en
| Synonym | chant d'acception | fr |
https://glossary.acousti.cloud/acoustic-adaptation
en
A process that promotes sound signals that are optimally transmitted in a given environment.
Reference: [1] Mathevon (2023), The Voices of Nature: How and Why Animals Communicate, pp. 305–308.
https://glossary.acousti.cloud/acoustic_adaptation_hypothesis
Acronym: AAH
en
"The hypothesis that animals sound signals have evolved to maximise transmission accounting for habitat properties [1,2]. Support for this hypothesis is mixed [3]." (from the Acoustic Index User's Guide)
https://glossary.acousti.cloud/acoustic_allometry
en
The principle of acoustic allometry—the larger the animal, the lower its calls’ fundamental frequency—is generally observed across terrestrial mammals. [1]
Reference: [1] Riondato I, Gamba M, Tan CL, et al. Allometric escape and acoustic signal features facilitate high-frequency communication in an endemic Chinese primate. 2021. Available at: http://link.springer.com/10.1007/s00359-021-01465-7.
https://glossary.acousti.cloud/acoustic_anthropocene
en
"The impact of people on natural soundscapes must have grown gradually with the human population growth on earth and the use of stones and metal for construction and tool making in the Stone, Bronze and Iron Ages. High-intensity anthropogenic sound events may have emerged with the invention of gunpowder in China, in the 9th century, used for mining, warfare and demolition. However, the invention of the steam engine, and the industrial revolution in general, by the end of the 18th century, can be regarded as the real start of steady growth of industrial and traffic noise in the western world. The automotive industry rose in the USA by the end of the 19th century and a considerable acceleration in car production happened soon after World War II, in which period commercial aviation also started to grow rapidly. Growth in noise pollution levels in the oceans roughly coincided with that in air, and was primarily related to the cold war increase of sonar use and the steady incline in global shipping activity associated with international trade. Seismic exploration for geophysical surveys started about 90 years ago, while pile driving for wind turbines at sea in coastal areas is a recent growth sector of the last decade." [1]
See also: anthropogenic noise, anthropophony
Reference: [1] Slabbekoorn H. Noise pollution. 2019. Available at: https://linkinghub.elsevier.com/retrieve/pii/S0960982219308632.
https://glossary.acousti.cloud/acoustic_aposematism
en
"The use of an acoustic signal by the prey to warn predators of their unpalatability." [1]
Reference: [1] Jacobs DS, Bastian A. Predator-Prey Interactions: Co-evolution between Bats and their Prey. Springer; 2016.
https://glossary.acousti.cloud/acoustic-avoidance
en
A process that increases the differences between sound signals from animals living at the same time in the same area.
Reference: [1] Mathevon (2023), The Voices of Nature: How and Why Animals Communicate, pp. 305–308.
https://glossary.acousti.cloud/acoustic-biodiversity
en
The totality of animal sound productions characteristic of an environment.
Reference: [1] Mathevon (2023), The Voices of Nature: How and Why Animals Communicate, pp. 305–308.
https://glossary.acousti.cloud/acoustic-biodiversity-indices
en
Quantitative measures derived from the analysis of sound recordings made in an environment and indicative of the diversity of living things in that environment.
Reference: [1] Mathevon (2023), The Voices of Nature: How and Why Animals Communicate, pp. 305–308.
https://glossary.acousti.cloud/acoustic-calibration
en
Reference: [1] Ross et al. (2023), Functional Ecology, glossary of key terms. https://doi.org/10.1111/1365-2435.14275
https://glossary.acousti.cloud/acoustic_climate_change
en
"Should we speak about 'acoustic climate change'? Due to the global nature of spread and taxonomically wide impact of noise pollution, it seems indeed reasonable to speak about acoustic climate change. Sound impact has typically been studied for a single source type and a single species. However, animals are often exposed to multiple noisy activities at the same time or in sequence, potentially in parallel with other disturbing factors such as changes in temperature regimes, drought, salinity, or invasive species. Investigating cumulative effects of different stressors will therefore be critical for our understanding of the ecological consequences of noise pollution and to come up with efficient measures for potential mitigation. We better treat noise pollution, like global warming, as an integral part of the global threat of human-induced climate change." [1]
Reference: [1] Slabbekoorn H. Noise pollution. 2019. Available at: https://linkinghub.elsevier.com/retrieve/pii/S0960982219308632.
https://glossary.acousti.cloud/acoustic_community
en
"A collection of soniferous species at a specific location and time [1]." (from the Acoustic Index User's Guide)
Reference: [1] Farina A, James P. The acoustic communities: Definition, description and ecological role. Biosystems. 2016;147:11-20. Available at: https://doi.org/10.1016/j.biosystems.2016.05.011.; Bradfer-Lawrence et al. (2023), Methods in Ecology and Evolution, glossary of key ecoacoustic terms. https://doi.org/10.1111/2041-210X.14194
https://glossary.acousti.cloud/acoustic-density
Acronym: ρ
en
Acoustic density of medium [kg m⁻³]. ρ (air) = 1.2 kg m⁻³; ρ (water) = 1000 kg m⁻³.
Reference: [1] Ewing (1989), Glossary of bioacoustic terms, pp. 226–227.
https://glossary.acousti.cloud/acoustic_ecology
en
"Ecology is the study of the relationship between living organisms and their environment. Acoustic ecology is thus the study of the effects of the acoustic environment or soundscape on the physical responses or behavioral characteristics of creatures living within it. Its particular aim is to draw attention to the imbalances which may have unhealthy or inimical effects." [1]
Reference: [1] Schafer RM. Our Sonic Environment and The Soundscape: the tuning of the World.; 1977.
https://glossary.acousti.cloud/acoustic-energy
en
Reference: [1] Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
https://glossary.acousti.cloud/acoustic_fovea
en
"An area of high sensitivity to a specific, narrow range of frequencies in the auditory pathway."[1]
Reference: [1] Jacobs DS, Bastian A. Predator-Prey Interactions: Co-evolution between Bats and their Prey. Springer; 2016.
https://glossary.acousti.cloud/acoustic_glints
en
"Changes in the amplitude and frequency in the echoes of bat calls from flapping insect wings perceived by the bat as amplitude and frequency glints against the constant echo from the background clutter." [1]
Reference: [1] Jacobs DS, Bastian A. Predator-Prey Interactions: Co-evolution between Bats and their Prey. Springer; 2016.
https://glossary.acousti.cloud/acoustic-impedance
en
Reference: [1] Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
https://glossary.acousti.cloud/acoustic_index
en
"Quantitative summary of the distribution and structure of acoustic energy in digital recordings of the soundscape. Metrics can reflect either temporal and/or frequency elements." (from the Acoustic Index User's Guide)
Reference: [1] Ross et al. (2023), Functional Ecology, glossary of key terms. https://doi.org/10.1111/1365-2435.14275; Bradfer-Lawrence et al. (2023), Methods in Ecology and Evolution, glossary of key ecoacoustic terms. https://doi.org/10.1111/2041-210X.14194
https://glossary.acousti.cloud/acoustic-localisation
en
Reference: [1] Ross et al. (2023), Functional Ecology, glossary of key terms. https://doi.org/10.1111/1365-2435.14275
https://glossary.acousti.cloud/acoustic_niche_hypothesis
Acronym: ANH
en
"The hypothesis that animals separate their calls by time and frequency to maximise their propagation by avoiding masking from other sounds. As acoustic space is a limited resource, species occupy an ‘acoustic niche’ that avoids species competing, allowing their signals to be transmitted more effectively [1]. There is mixed support for this hypothesis [2,3,4]." (from the Acoustic Index User's Guide)
https://glossary.acousti.cloud/acoustic-power
en
Reference: [1] Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
https://glossary.acousti.cloud/acoustic-signals
en
Mechanical disturbances (vibration waves) propagating in water or air. Vibration signals propagating through solids (e.g., soil) can also be considered as sounds.
Reference: [1] Mathevon (2023), The Voices of Nature: How and Why Animals Communicate, pp. 305–308.
https://glossary.acousti.cloud/acoustic_space
en
"The profile of a sound over a landscape. The acoustic space of any sound is that area over which it may be heard before it drops below the ambient sound level." [1]
Reference: [1] Schafer RM. Our Sonic Environment and The Soundscape: the tuning of the World.; 1977.
https://glossary.acousti.cloud/acoustic_startle_response
en
"A change in behaviour, usually involving a cessation of activity, in response to acoustic stimuli produced by a predator." [1]
Reference: [1] Jacobs DS, Bastian A. Predator-Prey Interactions: Co-evolution between Bats and their Prey. Springer; 2016.
https://glossary.acousti.cloud/active_space
en
"The active space of a signal is the area over which the signal is perceived by the receiver. We normally consider the active space of a signal, but we can also consider the active space of different signal components." [1]
Reference: [1] Page RA, Ryan MJ, Bernal XE. Be loved, be prey, be eaten. 2014.; Jarrett et al. (2025), Journal of Applied Ecology, glossary of key terms. https://doi.org/10.1111/1365-2664.70000
| Synonym | Detection space | en |
https://glossary.acousti.cloud/active_time
en
"Is the female able to remember a call over that silent interval, and if so, does call complexity influence for how long the call is remembered—what we refer to as the call’s active time?" [1]
Reference: [1] Page RA, Ryan MJ, Bernal XE. Be loved, be prey, be eaten. 2014.
https://glossary.acousti.cloud/aliasing
en
"Signal processing error caused by insufficient sampling rate, leading to the misidentification of frequencies of the original sound signal during digital representation." (from the Acoustic Index User's Guide)
Reference: [1] Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
https://glossary.acousti.cloud/allotonic
en
"Sound frequencies outside the range of frequencies under consideration." [1]
Reference: [1] Jacobs DS, Bastian A. Predator-Prey Interactions: Co-evolution between Bats and their Prey. Springer; 2016.
https://glossary.acousti.cloud/amplitude
en
"The maximum deviation of an oscillation (e.g. a sound wave) from its mean value. The amplitude of audible sound waves is perceived by human ears as the loudness of the sound." [1]
Reference: [1] Ragge DR, Reynolds WJ. The Songs of the Grasshoppers and Crickets of Western Europe. Colchester, Essex: Harley Books; 1998.; Lewis et al. (2021), Conservation Biology, glossary of specialist terms. https://doi.org/10.1111/cobi.13465; Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
https://glossary.acousti.cloud/amplitude_modulation
en
"Periodic modulation of a carrier frequency so that the carrier frequency remains unchanged and the amplitude fluctuates." [1]
Reference: [1] Ewing AW. Arthropod Bioacoustics: Neurobiology and Behaviour. Ithaca, New York: Comstock; 1989.; Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
https://glossary.acousti.cloud/amplitude-of-a-sound
en
The intensity of a sound. The amplitude (high, medium, low) of a sound is measured in decibels.
Reference: [1] Mathevon (2023), The Voices of Nature: How and Why Animals Communicate, pp. 305–308.
https://glossary.acousti.cloud/analogue_recorder
en
"An instrument for making analogue recordings of sound." [1]
Reference: [1] Ragge DR, Reynolds WJ. The Songs of the Grasshoppers and Crickets of Western Europe. Colchester, Essex: Harley Books; 1998.
https://glossary.acousti.cloud/analogue_recording
en
"(on magnetic tape) A recording in which the sound is represented by a continuously variable magnetic charge (as opposed to a digital recording)." [1]
Reference: [1] Ragge DR, Reynolds WJ. The Songs of the Grasshoppers and Crickets of Western Europe. Colchester, Essex: Harley Books; 1998.
https://glossary.acousti.cloud/angular-frequency
Acronym: ω
en
Angular frequency: ω = 2π radians.
Reference: [1] Ewing (1989), Glossary of bioacoustic terms, pp. 226–227.
ANH, see acoustic niche hypothesis
https://glossary.acousti.cloud/anspringlaut
de
"Mounting song of male at end of courtship." [1]
Reference: [1] Broughton WB. Glossarial Index. In: Acoustic Behavior of Animals. Elsevier; 1963.
https://glossary.acousti.cloud/anthropogenic_noise
en
"Noise pollution refers to the elevation of natural ambient noise levels due to sound-generating human activities, which may have detrimental consequences for humans and animals alike. Sounds of this kind are often referred to as anthropogenic noise. Some of these sounds are deliberate and wanted, such as music, sirens, seismic survey sounds or military sonar. Most anthropogenic noise, however, is an unwanted by-product, such as traffic or generator noise, and impulsive sounds from pile driving and explosives." [1]
See also: anthropophony, noise pollution
Reference: [1] Slabbekoorn H. Noise pollution. 2019. Available at: https://linkinghub.elsevier.com/retrieve/pii/S0960982219308632.
https://glossary.acousti.cloud/anthropophony
en
"all of the sounds we humans generate. Some of these are controlled, like music, language or theatre. But most of what humans produce is chaotic or incoherent - sometimes referred to as noise." [1]
"Sounds of human origin, including human speech [2]. Technophony is a subcomponent of anthropophony referring to machine generated sounds, excluding human speech and music [3]." (from the Acoustic Index User's Guide)
| Synonym | anthrophony | en |
https://glossary.acousti.cloud/anti-alarm_signal
en
"(= reassurance call) in mice." [1]
Reference: [1] Broughton WB. Glossarial Index. In: Acoustic Behavior of Animals. Elsevier; 1963.
https://glossary.acousti.cloud/anti-aliasing-filter
en
Reference: [1] Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
https://glossary.acousti.cloud/antidromism
en
"Bilateral alternation of stridulatory movements; stridulatory anti-phasis." [1]
Reference: [1] Broughton WB. Glossarial Index. In: Acoustic Behavior of Animals. Elsevier; 1963.
https://glossary.acousti.cloud/antiphasis
en
Out of phase by half a period.
Synonyms: fully out of phase
https://glossary.acousti.cloud/antiphony
en
"Duetting in which the partners take up the burden of the song in alternation, with such accuracy that the observer may not be aware that two birds are singing. Part of the courtship and post-courtship ritual maintaining the pair bond." [1]
Reference: [1] Broughton WB. Glossarial Index. In: Acoustic Behavior of Animals. Elsevier; 1963.
https://glossary.acousti.cloud/appeau
fr
"simulated bird call, sonic decoy." [1]
Reference: [1] Broughton WB. Glossarial Index. In: Acoustic Behavior of Animals. Elsevier; 1963.
https://glossary.acousti.cloud/arms-race
en
The evolutionary escalation between a communication signal and the resistance of the individual receiver to respond to this signal. The sender produces a signal with increasingly exaggerated characteristics, while the receiver becomes increasingly reluctant to respond to the signal. A common metaphor for this phenomenon is the Red Queen’s instruction to Alice that they must run to stay in the same place.
Reference: [1] Mathevon (2023), The Voices of Nature: How and Why Animals Communicate, pp. 305–308.
https://glossary.acousti.cloud/array
en
"Multiple microphones operating in parallel, often deployed in a grid. Could be placed to cover a large survey area or to estimate direction and distance from sound source in a smaller area [1]." (from the Acoustic Index User's Guide)
Reference: [1] Blumstein DT, Mennill DJ, Clemins P, et al. Acoustic monitoring in terrestrial environments using microphone arrays: applications, technological considerations and prospectus. Journal of Applied Ecology. 2011;48(3):758-767. Available at: https://doi.org/10.1111/j.1365-2664.2011.01993.x.; Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4; Ross et al. (2023), Functional Ecology, glossary of key terms. https://doi.org/10.1111/1365-2435.14275
| Synonym | Acoustic array | en | |
| Synonym | Acoustic sensor array | en |
ARU, see autonomous recording unit
https://glossary.acousti.cloud/attenuation
en
"The loss of energy in a sound wave as it traverses media such as air, water, or soil." (from the Acoustic Index User's Guide)
https://glossary.acousti.cloud/audible_sound
en
"Sounds that can be heard by the human ear, generally considered to span 20 Hz to 20 kHz." (from the Acoustic Index User's Guide)
https://glossary.acousti.cloud/audience-effect
en
When an animal reacts to a communication signal or changes its signal production based on the individuals around it.
Reference: [1] Mathevon (2023), The Voices of Nature: How and Why Animals Communicate, pp. 305–308.
https://glossary.acousti.cloud/audiogram
en
"A chart or table relating hearing loss for pure tones to frequency." [1]
Reference: [1] Broughton WB. Glossarial Index. In: Acoustic Behavior of Animals. Elsevier; 1963.
https://glossary.acousti.cloud/audiospectrogram
en
"A visual record of the frequency spectrum of a sound on a time-scale (obtained from an audiospectrograph)." [1]
"correctly used not for [audiospectrum], but for the graph of its variation with time." [2]
Reference: [1] Ragge DR, Reynolds WJ. The Songs of the Grasshoppers and Crickets of Western Europe. Colchester, Essex: Harley Books; 1998.
https://glossary.acousti.cloud/audiospectrograph
en
"Equipment for producing an audiospectrogram." [1]
Reference: [1] Ragge DR, Reynolds WJ. The Songs of the Grasshoppers and Crickets of Western Europe. Colchester, Essex: Harley Books; 1998.
https://glossary.acousti.cloud/auditory_organ
en
An organ used by an organism for hearing.
"An insect will be said to hear when it is demonstrably responsive to sound. An auditory organ is one which can be shown to mediate the above response or which can itself be shown by more direct means to respond to sound." [1]
Reference: [1] Pumphrey RJ. Hearing in Insects. Biological Reviews. 1940;15(1):107 - 132. Available at: http://www.blackwell-synergy.com/toc/brv/15/1.
https://glossary.acousti.cloud/aural_masking
en
"The increase expressed in decibels in the threshold of hearing of the masked sound due to the presence of the masking sound." [1]
Reference: [1] Broughton WB. Glossarial Index. In: Acoustic Behavior of Animals. Elsevier; 1963.; Ross et al. (2023), Functional Ecology, glossary of key terms. https://doi.org/10.1111/1365-2435.14275
| Synonym | Acoustic masking | en |
https://glossary.acousti.cloud/aural_space
en
"The space on any graph which results from plotting of the various dimensions of sound against one another. For convenience in reading usually only two dimensions are plotted at once. Thus time may be plotted against frequency, frequency against amplitude, or amplitude against time. Aural space is thus merely a notational convention and should not be confused with acoustic space, which is an expression of the profile of a sound over the landscape." [1]
Reference: [1] Schafer RM. Our Sonic Environment and The Soundscape: the tuning of the World.; 1977.
https://glossary.acousti.cloud/auricle
en
"A flap sometimes partly concealing the tympanum." [1]
Reference: [1] Ragge DR, Reynolds WJ. The Songs of the Grasshoppers and Crickets of Western Europe. Colchester, Essex: Harley Books; 1998.
https://glossary.acousti.cloud/autonomous_recording_unit
Acronym: ARU
en
"Automated audio recording devices for acoustic monitoring. These can be left in the field unattended and programmed to record at specific times, creating a cost-effective and non-invasive alternative to traditional field surveys." (from the Acoustic Index User's Guide)
https://glossary.acousti.cloud/backward_masking
en
"Overlap of background echoes with echoes from the target making it difficult for echolocating bats that do not use acoustic glints to detect the echoes from the target." [1]
Reference: [1] Jacobs DS, Bastian A. Predator-Prey Interactions: Co-evolution between Bats and their Prey. Springer; 2016.
https://glossary.acousti.cloud/balz
de
"courtship display, serenade." [1]
Reference: [1] Broughton WB. Glossarial Index. In: Acoustic Behavior of Animals. Elsevier; 1963.
https://glossary.acousti.cloud/band-level
en
Reference: [1] Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
https://glossary.acousti.cloud/bandpass_filter
en
"A circuit (electronic or neuronal) which allows the transmission of a specific range of frequencies." [1]
Reference: [1] Ewing AW. Arthropod Bioacoustics: Neurobiology and Behaviour. Ithaca, New York: Comstock; 1989.; Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
| Synonym | Band-pass filter | en |
https://glossary.acousti.cloud/beamforming
en
Reference: [1] Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
https://glossary.acousti.cloud/beam-pattern
en
Reference: [1] Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
https://glossary.acousti.cloud/beat
en
"(1) music: rhythmic pulsation, as e.g. three beats to the bar, etc; Sotavalta extends for bird song as follows: the smallest rhythmic unit; a single rhythmic accent that can be repeated after successive intervals, regular or irregular. Between beats may be sub-beats of a different order.
(2) physics: the periodic variations of amplitude resulting from the addition of two periodic quantities of the same kind but slightly different frequency." [1]
Reference: [1] Broughton WB. Glossarial Index. In: Acoustic Behavior of Animals. Elsevier; 1963.
https://glossary.acousti.cloud/bi-syllabic
en
"hybrid word; the correct form is disyllabic." [1]
Synonyms: bisyllabic
Reference: [1] Broughton WB. Glossarial Index. In: Acoustic Behavior of Animals. Elsevier; 1963.
https://glossary.acousti.cloud/bin
en
"Partitioning of a spectogram into equal frequency intervals." (from the Acoustic Index User's Guide)
https://glossary.acousti.cloud/binaural_hearing
en
"Hearing with two ears. The counterpart is uniaural, not the hybrid monaural." [1]
Reference: [1] Broughton WB. Glossarial Index. In: Acoustic Behavior of Animals. Elsevier; 1963.
https://glossary.acousti.cloud/bioacoustician
en
a collector and student of wildlife sounds [1]
Synonyms: bio-acoustician
Reference: [1] Krause BL. Voices of the Wild. Yale University Press; 2015.
https://glossary.acousti.cloud/bioacoustics
en
"The study of sounds living animals produce." [1]
"The science of sound-production and hearing in living organisms." [2]
"Combined study of biology and acoustics focussed on the production, transmission, and detection of sounds by animals for communication purposes." (from the Acoustic Index User's Guide)
Synonyms: bio-acoustics
https://glossary.acousti.cloud/biophony
en
"the collective sound produced by all living organisms that reside in a particular biome." [1]
"Sounds of biological origin. For example, bird song or frog calls [2]." (from the Acoustic Index User's Guide)
https://glossary.acousti.cloud/bit-depth
en
Reference: [1] Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
https://glossary.acousti.cloud/bombilate
en
To hum or buzz.
According to Oxford English Dictionary "Rare. Apparently only attested in dictionaries or glossaries.".
https://glossary.acousti.cloud/bombinate
en
To buzz or hum.
https://wordsmith.org/words/bombinate.html
https://glossary.acousti.cloud/build-up_time
en
"The interval of time that elapses between the instant when the envelope of a transmitted wave of specified frequency is first received, and the instant when it first attains a specified fraction of its steady-state magnitude. Hence for the animal emission: lapse time from the beginning of a given wave-train to the instant it attains its maximum amplitude." [1]
Synonyms: building-up time
Reference: [1] Broughton WB. Glossarial Index. In: Acoustic Behavior of Animals. Elsevier; 1963.
c, see Propagation velocity of sound
c, see celerity
https://glossary.acousti.cloud/call
en
Reference: [1] Lewis et al. (2021), Conservation Biology, glossary of specialist terms. https://doi.org/10.1111/cobi.13465
https://glossary.acousti.cloud/calling_song
en
"The song produced by an isolated male." [1]
Reference: [1] Ragge DR, Reynolds WJ. The Songs of the Grasshoppers and Crickets of Western Europe. Colchester, Essex: Harley Books; 1998.
| Synonym | Chant d'appel | fr | |
| Synonym | Chant ordinaire | fr | |
| Synonym | Gewöhnlicher Gesang | de | |
| Synonym | Kutsulaulut | fi | |
| Synonym | Lockgesang | de | |
| Synonym | Normal song | en | |
| Synonym | Rufgesang | de |
https://glossary.acousti.cloud/cancrizans
en
"(music): imitation al rovescio, i.e. repetition of a phrase or figure in reverse in another part. By extension, applied to the playback to experimental animals of their own recorded song in reverse." [1]
Reference: [1] Broughton WB. Glossarial Index. In: Acoustic Behavior of Animals. Elsevier; 1963.
| Synonym | contrepoint de l'écrevisse | fr |
https://glossary.acousti.cloud/carrier_frequency
en
"The underlying frequency of a signal before modification such as amplitude modulation." [1]
Reference: [1] Ewing AW. Arthropod Bioacoustics: Neurobiology and Behaviour. Ithaca, New York: Comstock; 1989.
https://glossary.acousti.cloud/carrier_wave
en
"The carrier wave is the fundamental wave of a resonant song." [1]
Reference: [1] Ragge DR, Reynolds WJ. The Songs of the Grasshoppers and Crickets of Western Europe. Colchester, Essex: Harley Books; 1998.
https://glossary.acousti.cloud/castanets
en
"One reasonably well-understood example of a percussive mechanism involving two-body parts is found in members of the Australian moth genus, Hecatesi (Bailey, 1978). In these moths an area of the costae of the fore wings is modified to form small hard knobs which have been called castanets. These are repeatedly struck together at the top of the wing stroke to produce sounds which have given these insects the popular name of 'whistling moths'." [1]
Reference: [1] Ewing AW. Arthropod Bioacoustics: Neurobiology and Behaviour. Ithaca, New York: Comstock; 1989.
https://glossary.acousti.cloud/categorization
en
The mechanism by which an animal responds to the continuous variation of a physical stimulus by forming categories.
Reference: [1] Mathevon (2023), The Voices of Nature: How and Why Animals Communicate, pp. 305–308.
https://glossary.acousti.cloud/celerity
Acronym: c
en
Propagation velocity of sound (ms⁻¹).
In air at sea level c ≃ 340ms⁻¹.
In fresh water c ≃ 1430ms⁻¹. The excat value depends upon pressure, temperature and tonicity; c in sea water is usually taken to be 1500ms⁻¹. [1]
Reference: [1] Ewing AW. Arthropod Bioacoustics: Neurobiology and Behaviour. Ithaca, New York: Comstock; 1989.
https://glossary.acousti.cloud/chain-of-information-transmission
en
The sender-signal-receiver unit, as well as the processes of encoding information (by the sender), transmitting information (propagation of the signal in the environment), and decoding information (by the receiver). All elements of the information transmission chain can be affected by noise.
Reference: [1] Mathevon (2023), The Voices of Nature: How and Why Animals Communicate, pp. 305–308.
https://glossary.acousti.cloud/character-shift
en
The increase in differences that allow a distinction, for receivers, between animal populations living in the same location.
Reference: [1] Mathevon (2023), The Voices of Nature: How and Why Animals Communicate, pp. 305–308.
https://glossary.acousti.cloud/chirp
en
"A sound which may consist of one or more syllables or pulses and which is normally heard by the human ear as a unitary event. Usually applied to the songs of crickets and related insects." [1]
"as equated to one movement (= Silbe, G.), Broughton, now abandoned and deprecated as over-restricted." [2]
"Preferred unitary dictionary sense, as first parameter of analysis: the shortest unitary rhythm element of a sound emission that can readily be distinguished as such by the human ear." [2]
The BioAcoustica preference is to use echeme.
See also: echeme
https://glossary.acousti.cloud/chorus
en
"A group of animals singing/calling together." [1]
Reference: [1] Jacobs DS, Bastian A. Predator-Prey Interactions: Co-evolution between Bats and their Prey. Springer; 2016.
| Synonym | communal singing | en |
https://glossary.acousti.cloud/clipping
en
"When amplifiers receive signals above their decibel limit, sound is distorted. The upper and lower limits of the soundwave are cut off or ‘clipped’." (from the Acoustic Index User's Guide)
https://glossary.acousti.cloud/closed-ended-learner
en
Reference: [1] Lewis et al. (2021), Conservation Biology, glossary of specialist terms. https://doi.org/10.1111/cobi.13465
https://glossary.acousti.cloud/clutter
en
"In the context of echolocation, it is the echoes from the non-target objects e.g. background vegetation." [1]
Reference: [1] Jacobs DS, Bastian A. Predator-Prey Interactions: Co-evolution between Bats and their Prey. Springer; 2016.
CNS, see Central nervous system
https://glossary.acousti.cloud/communication
en
The transfer of information between one or several senders and one or several receivers.
Reference: [1] Mathevon (2023), The Voices of Nature: How and Why Animals Communicate, pp. 305–308.
https://glossary.acousti.cloud/communication-network
en
The set of individuals that can transmit and receive sound signals between them.
Reference: [1] Mathevon (2023), The Voices of Nature: How and Why Animals Communicate, pp. 305–308.
https://glossary.acousti.cloud/compass
en
"(of an emission apparatus): the range between highest and lowest frequencies emissable, see sound spectrum. Preferable to range, because of the latter's use in the topographic sense." [1]
"(of a receptor): the range of frequencies receivable, from the highest to the lowest." [1]
Reference: [1] Broughton WB. Glossarial Index. In: Acoustic Behavior of Animals. Elsevier; 1963.
https://glossary.acousti.cloud/complex_free_vibrations
en
"Free vibrations which are not simple sine-waves of steady amplitude." [1]
Reference: [1] Broughton WB. Glossarial Index. In: Acoustic Behavior of Animals. Elsevier; 1963.
https://glossary.acousti.cloud/constant-bandwidth
en
Reference: [1] Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
https://glossary.acousti.cloud/continuous_waves
en
"Waves in which the successive oscillations are identical as soon as a steady rate is achieved." [1]
Reference: [1] Broughton WB. Glossarial Index. In: Acoustic Behavior of Animals. Elsevier; 1963.; Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
| Synonym | Continuous wave | en |
https://glossary.acousti.cloud/cost-of-a-signal
en
The processes that cause the emission of a signal to decrease the probability of survival of the sender or its ability to have offspring.
Reference: [1] Mathevon (2023), The Voices of Nature: How and Why Animals Communicate, pp. 305–308.
https://glossary.acousti.cloud/courtship_song
en
"The special song produced by a male when close to a female." [1]
Reference: [1] Ragge DR, Reynolds WJ. The Songs of the Grasshoppers and Crickets of Western Europe. Colchester, Essex: Harley Books; 1998.
| Synonym | Chant de cour | fr | |
| Synonym | Kosiolaulut | fi | |
| Synonym | Werbegesang | de |
https://glossary.acousti.cloud/crepitation
en
"The production during flight (or by flight-like vibration of the wings while on the ground) of a rattling, whirring or buzzing sound; the sound so produced." [1]
"A crackling sound produced by some grasshoppers by rapidly opening their wings." [2]
| Synonym | Lentoäänet | fi |
https://glossary.acousti.cloud/cross-correlation
en
Reference: [1] Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
https://glossary.acousti.cloud/crypsis
en
"The minimization of detection through the use of visual, chemical, tactile, electric and acoustic traits when potentially detectable by an observer." [1]
Reference: [1] Jacobs DS, Bastian A. Predator-Prey Interactions: Co-evolution between Bats and their Prey. Springer; 2016.
https://glossary.acousti.cloud/cultural-variation
en
Reference: [1] Lewis et al. (2021), Conservation Biology, glossary of specialist terms. https://doi.org/10.1111/cobi.13465
https://glossary.acousti.cloud/cycle
en
"of a periodic quantity - a complete repetition of the series of changes that take place during the period of a recurring variable quantity.
By extension, cycle is applied to recurring quantities even when successive cycles are not identical." [1]
Reference: [1] Broughton WB. Glossarial Index. In: Acoustic Behavior of Animals. Elsevier; 1963.
https://glossary.acousti.cloud/damped_wave
en
"waves whose amplitude progressively decrease with respect to time." [1]
Reference: [1] Broughton WB. Glossarial Index. In: Acoustic Behavior of Animals. Elsevier; 1963.
https://glossary.acousti.cloud/damping
en
"The effect of the dissipation of energy of an oscillating system on its operation." [1]
Reference: [1] Broughton WB. Glossarial Index. In: Acoustic Behavior of Animals. Elsevier; 1963.
dB, see decibel
https://glossary.acousti.cloud/dear-enemy-effect
en
When a territorial animal reacts less violently to the acoustic signals of a familiar neighbor than to those of an unknown individual.
Reference: [1] Mathevon (2023), The Voices of Nature: How and Why Animals Communicate, pp. 305–308.
https://glossary.acousti.cloud/decay_time
en
"Lapse of time from the instant maximum amplitude of a waveform begins to decrease until it has fallen to zero or a specified level near zero." [1]
See also: build-up time
Reference: [1] Broughton WB. Glossarial Index. In: Acoustic Behavior of Animals. Elsevier; 1963.
https://glossary.acousti.cloud/decibel
Acronym: dB
en
"One tenth of a bel, a logarithmic unit used to compare two levels of power." [1]
"Two powers P1 and P2 are said to be separated by an interval of n bels (or 10n decibels) when n=log10(P1/P2). The unit is dimensionless." [2]
https://glossary.acousti.cloud/decidecade
en
Reference: [1] Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
https://glossary.acousti.cloud/delay-and-sum-beamformer
en
Reference: [1] Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
https://glossary.acousti.cloud/desperation_call
en
"More precise term for one category of distress call." [1]
Synonyms: desperation-call
Reference: [1] Broughton WB. Glossarial Index. In: Acoustic Behavior of Animals. Elsevier; 1963.
https://glossary.acousti.cloud/detection_distance
en
"The maximum distance from a recorder at which a sound signal can be detected. The distance varies depending on the target species and sound attenuation rate in the survey environment [1]." (from the Acoustic Index User's Guide)
Reference: [1] Sugai LSM, Desjonquères C, Silva TSF, Llusia D. A roadmap for survey designs in terrestrial acoustic monitoring. Remote Sensing in Ecology and Conservation. 2020;6(3):220-235. Available at: https://doi.org/10.1002/rse2.131.
DFT, see Discrete Fourier transform
https://glossary.acousti.cloud/dialect
en
The geographic variation in the vocalizations of an animal species.
Reference: [1] Mathevon (2023), The Voices of Nature: How and Why Animals Communicate, pp. 305–308.; Lewis et al. (2021), Conservation Biology, glossary of specialist terms. https://doi.org/10.1111/cobi.13465
https://glossary.acousti.cloud/diel
en
"involving a 24-hour period. The word is an illegitimate neologism, coined in the absence of need; where daily will not do, owing to suggestion of daytime occurrence, nycthemeral will, and is of respectable antiquity and regularly formed." [1]
Reference: [1] Broughton WB. Glossarial Index. In: Acoustic Behavior of Animals. Elsevier; 1963.
https://glossary.acousti.cloud/diel_cycle
en
"The 24-hour daily cycle." (from the Acoustic Index User's Guide)
https://glossary.acousti.cloud/digital_recorder
en
"An instrument for making digital recordings of sound." [1]
Reference: [1] Ragge DR, Reynolds WJ. The Songs of the Grasshoppers and Crickets of Western Europe. Colchester, Essex: Harley Books; 1998.
https://glossary.acousti.cloud/digital_recording
en
"A recording in which the sound is represented by numerous consecutive samples expressed in binary digits (as opposed to an analogue recording)." [1]
Reference: [1] Ragge DR, Reynolds WJ. The Songs of the Grasshoppers and Crickets of Western Europe. Colchester, Essex: Harley Books; 1998.
https://glossary.acousti.cloud/digitize
en
"To convert an analogue recording to a digital recording." [1]
Reference: [1] Ragge DR, Reynolds WJ. The Songs of the Grasshoppers and Crickets of Western Europe. Colchester, Essex: Harley Books; 1998.
https://glossary.acousti.cloud/diplosyllable
en
A syllable in which sound is produced by both to- and fro- movements of the stridulatory apparatus.
"A syllable in which sound is produced by opening and closing wing-strokes in the Ensifera, and both upward and downward leg-strokes in the gomphocerine grasshoppers." [1]
Reference: [1] Ragge DR, Reynolds WJ. The Songs of the Grasshoppers and Crickets of Western Europe. Colchester, Essex: Harley Books; 1998.
https://glossary.acousti.cloud/DFT
Acronym: DFT
en
Discrete Fourier transform
https://glossary.acousti.cloud/DWPT
Acronym: DWPT
en
Discrete wavelet packet transform
https://glossary.acousti.cloud/DPOAE
Acronym: DPOAE
en
Distortion product otoacoustic emission
https://glossary.acousti.cloud/doppelsilbe
de
"diplosyllable, not disyllabic sound." [1]
Reference: [1] Broughton WB. Glossarial Index. In: Acoustic Behavior of Animals. Elsevier; 1963.
https://glossary.acousti.cloud/Doppler_effect
en
"Change in apparent frequency of a periodic signal such as a pressure wave or light due to movement of the emitter or receiver." [1]
"The change in the observed frequency of a wave caused by the time rate of change in the length of the path of travel between the source and the observer." [2]
| Synonym | Doppler shift | en |
https://glossary.acousti.cloud/Doppler_shift_compensation
en
"The emission of echolocation calls at frequencies lower than the hearing sensitivity of the acoustic fovea so that the upward shift in frequency of the echo, as a result of the relative velocity of the bat to the target, ensures that frequency of the echo is within frequency range of the acoustic fovea." [1]
Reference: [1] Jacobs DS, Bastian A. Predator-Prey Interactions: Co-evolution between Bats and their Prey. Springer; 2016.
https://glossary.acousti.cloud/downsweep
en
Reference: [1] Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
DPOAE, see Distortion product otoacoustic emission
DRN, see Dynamic range normalization
https://glossary.acousti.cloud/duty_cycle
en
"The ratio of the duration of the call to the period of the call (call duration + time to next call). Usually expressed as a percentage." [1]
Reference: [1] Jacobs DS, Bastian A. Predator-Prey Interactions: Co-evolution between Bats and their Prey. Springer; 2016.
DWPT, see Discrete wavelet packet transform
https://glossary.acousti.cloud/dynamic-information
en
Information about the characteristics of the sender that may vary quickly (e.g., emotions or aggression).
Reference: [1] Mathevon (2023), The Voices of Nature: How and Why Animals Communicate, pp. 305–308.
https://glossary.acousti.cloud/DRN
Acronym: DRN
en
Dynamic range normalization
https://glossary.acousti.cloud/eavesdropper
en
"In the case of sexual advertisement signals, the intended receivers are prospective mates, usually female conspecifics. Other receivers can also detect and respond to signals even if there was no selection on the sender to communicate with them. We refer to these receivers as eavesdroppers or unintended receivers. It is important to note that the terms intended and unintended should not imply intentionality but instead refer to hypotheses about the selection forces that favored the evolution of these signals. With few exceptions, senders and receivers do not communicate in a private channel. The world is populated by unintended receivers, eavesdroppers who are attendant to the signals of senders, often to the demise of senders." [1]
Synonyms: unintended receiver
Reference: [1] Page RA, Ryan MJ, Bernal XE. Be loved, be prey, be eaten. 2014.
https://glossary.acousti.cloud/eavesdropping
en
When an individual listens to a sound signal that was not intended for them and obtains information from it.
Reference: [1] Mathevon (2023), The Voices of Nature: How and Why Animals Communicate, pp. 305–308.
https://glossary.acousti.cloud/echeme
en
"(pronounced eck'eem) A first-order assemblage of syllables." [1]
Reference: [1] Ragge DR, Reynolds WJ. The Songs of the Grasshoppers and Crickets of Western Europe. Colchester, Essex: Harley Books; 1998.; Lewis et al. (2021), Conservation Biology, glossary of specialist terms. https://doi.org/10.1111/cobi.13465
| Synonym | Phrase | fr | |
| Synonym | Vers | de | |
| Synonym | Verse | en |
https://glossary.acousti.cloud/echeme-sequence
en
"A first-order assemblage of echemes." [1]
Reference: [1] Ragge DR, Reynolds WJ. The Songs of the Grasshoppers and Crickets of Western Europe. Colchester, Essex: Harley Books; 1998.
| Synonym | Strophe | de |
https://glossary.acousti.cloud/echte_Gehorsinn
de
"True sense of hearing", defined by von Buddenbrock (1937) [1] as a sense detected by a resonating organ.
"Wir werden einen Gehorsinn nur dann als bewiesen ansehen, wenn sich nachweisen lasst, dass das betreffende Sinnesorgan seiner Struktur nach spezifisch auf die Wahrnehmung von Schallwellen eingestellt ist. Das Kriterium des Gehorsinns ist daher das besonders ausgebildete Gehororgan, welches als charac- terisches Element in stets wiederkehrende Weise eine oder mehrere Membranen besitzt, die zum Mitschwingen durch Resonanz befahigt sind.” [1]
This distinction between hearing and other vibratory senses, such as touch, is dismissed as anthropocentric by Pumphrey [2] : "Such a definition is clearly founded on the human analogy. The first sentence seems to imply that there is some fundamental distinction between sound waves and other mechanical stimuli, presumably on the grounds that touch and hearing are distinct in man, for the assumption can hardly be maintained in the face of the evidence bearing on the evolution of sound receptors either in vertebrate or other animals. But the second sentence goes even further. The final criterion of an auditory organ is not its specific sensitivity to sound waves, but a resemblance in certain arbitrary structural particulars to the human ear. If this criterion be accepted, fish are deaf by definition ... and only those insects with tympanic organs can hear. It is then necessary to invent an other sense, sensitivity to vibrations or Erschütterungssinn to explain the responsiveness to sound of animals which have no echter Gehorsinn."
https://glossary.acousti.cloud/ecoacoustics
en
"Discipline using environmental sound to study biodiversity and ecology. Differs from bioacoustics in that it considers the role of sound in ecological processes rather than solely as a communication signal [1]." (from the Acoustic Index User's Guide)
Reference: [1] Sueur J, Farina A. Ecoacoustics: the Ecological Investigation and Interpretation of Environmental Sound. Biosemiotics. 2015;8(3):493-502. Available at: https://doi.org/10.1007/s12304-015-9248-x.
https://glossary.acousti.cloud/ecological-selection
en
A process that favors sound signals that are best propagated in the environment where they are used.
Reference: [1] Mathevon (2023), The Voices of Nature: How and Why Animals Communicate, pp. 305–308.
EER, see Equal error rate
https://glossary.acousti.cloud/element
en
Reference: [1] Lewis et al. (2021), Conservation Biology, glossary of specialist terms. https://doi.org/10.1111/cobi.13465
https://glossary.acousti.cloud/elementary_waveform
en
"The hypothetical continuous wave-form to which any given wave-train emitted by an animal approximates; the basic signal." [1]
Synonyms: elementary vibration
Reference: [1] Broughton WB. Glossarial Index. In: Acoustic Behavior of Animals. Elsevier; 1963.
https://glossary.acousti.cloud/erschutterungssinn
de
Term devised by von Buddenbrock [1] for animals that can detect vibration without a resonant organ (i.e. those without echte Gehörsinn).
This distinction is criticised by Pumphrey [2] : "This invention has had unfortunate consequences, because of the tendency to regard sensitivity to vibrations as a special kind of touch sense in quite a separate category from true hearing instead of regarding it as including true hearing, which would be both logical and consistent with what is known of the evolution of hearing organs."
https://glossary.acousti.cloud/evolutionarily-stable-equilibrium
en
A communication behavior that characterizes the majority of individuals in a population and is never superseded by another: any variation is counter-selected. Also referred to as an evolutionarily stable strategy.
Reference: [1] Mathevon (2023), The Voices of Nature: How and Why Animals Communicate, pp. 305–308.
https://glossary.acousti.cloud/evolutionary-causes-of-communication
en
Processes that explain the development of communication throughout the history of a species. The evolutionary causes, in the long term, concern the processes of natural selection in particular (including sexual selection), as well as genetic and cultural drifts.
Reference: [1] Mathevon (2023), The Voices of Nature: How and Why Animals Communicate, pp. 305–308.
https://glossary.acousti.cloud/exaptation
en
A mechanism occurring during evolution where the function of a preexisting trait is redirected to another function (e.g., the drumming behavior of woodpeckers, originally used to find food, has become a means of emitting an acoustic communication signal for recognition within the species).
Reference: [1] Mathevon (2023), The Voices of Nature: How and Why Animals Communicate, pp. 305–308.
FA, see False acceptance
FA, see False alarm
https://glossary.acousti.cloud/facultative
en
"Optional." [1]
Reference: [1] Ragge DR, Reynolds WJ. The Songs of the Grasshoppers and Crickets of Western Europe. Colchester, Essex: Harley Books; 1998.
https://glossary.acousti.cloud/false-colour_spectrogram
Acronym: FCS
en
"A spectrogram-like image produced by combining three acoustic indices which are mapped using red, green and blue channels. It enables soundscapes to be rapidly visualised across a range of temporal scales [1]." (from the Acoustic Index User's Guide)
Reference: [1] Towsey M, Zhang L, Cottman-Fields M, Wimmer J, Zhang J, Roe P. Visualization of Long-duration Acoustic Recordings of the Environment. Procedia Computer Science. 2014;29:703-712. Available at: https://doi.org/10.1016/j.procs.2014.05.063.; Bradfer-Lawrence et al. (2023), Methods in Ecology and Evolution, glossary of key ecoacoustic terms. https://doi.org/10.1111/2041-210X.14194
https://glossary.acousti.cloud/far_field
en
"Distance greater than one wavelength from a sound source. In this region pressure and particle velocity are in phase and behave as plane waves." [1]
Reference: [1] Ewing AW. Arthropod Bioacoustics: Neurobiology and Behaviour. Ithaca, New York: Comstock; 1989.; Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
https://glossary.acousti.cloud/fast_fourier_transform
Acronym: FFT
en
"An algorithm that provides information about the energy distribution across frequencies by transforming a continuous time series into individual spectral components (differences across frequency bands)." (from the Acoustic Index User's Guide)
Reference: [1] Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
FB, see Filter bank
FCS, see false-colour spectrogram
FFT, see fast Fourier transform
https://glossary.acousti.cloud/figure
en
"the smallest melodic unit which has a pattern; consist of one or more beats (and/or sub-beats). (Sotavalta)." [1]
Synonyms: melodic figure
Reference: [1] Broughton WB. Glossarial Index. In: Acoustic Behavior of Animals. Elsevier; 1963.
https://glossary.acousti.cloud/first-order_assemblage
en
"An assemblage one level in rank above it's specified components." [1]
Reference: [1] Ragge DR, Reynolds WJ. The Songs of the Grasshoppers and Crickets of Western Europe. Colchester, Essex: Harley Books; 1998.
FN, see False negative
https://glossary.acousti.cloud/forced_vibration
en
"A vibration directly maintained in a system by a periodic force, and having the frequency of the force." [1]
Synonyms: forced oscillation
Reference: [1] Broughton WB. Glossarial Index. In: Acoustic Behavior of Animals. Elsevier; 1963.
https://glossary.acousti.cloud/formant
en
"Principal frequencies in the sound spectrum of a human (or analogous) utterance, which, for a particular individual, are diagnostic of particular speech-elements, especially vowels in which some three characteristic formants (different for each vowel and for each individual) are present. They are resonance frequencies originating in the vocal tract , and in some but not all cases can be attributed to parts of it. The individual differences, especially between male and female, in the formant complement appropriate to a given vowel might be expected to lead to confusion by a hearer, and indeed Broadbent succeeded in making an experimental audience identify one and the same synthetic sound as bit it one context and bet in another; the diagnostic properties of the formant-set of a particular individual are thus relative to those of the rest of the utterance, which is taken into account, computer-wise, by the hearer." [1]
Synonyms: formant frequencies
Reference: [1] Broughton WB. Glossarial Index. In: Acoustic Behavior of Animals. Elsevier; 1963.
https://glossary.acousti.cloud/formants
en
Reinforced voice frequencies when sound waves travel through the vocal tract.
Reference: [1] Mathevon (2023), The Voices of Nature: How and Why Animals Communicate, pp. 305–308.
https://glossary.acousti.cloud/forward_masking
en
"Overlap of the emitted echolocation call with the echo reflected from a target because the target is too close to the bat making. The echo is said to be masked for low duty cycle bats because the bats hearing is still 'switched off' to avoid self-deafening." [1]
Reference: [1] Jacobs DS, Bastian A. Predator-Prey Interactions: Co-evolution between Bats and their Prey. Springer; 2016.
https://glossary.acousti.cloud/fourier-transform
en
Reference: [1] Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
FR, see False rejection
https://glossary.acousti.cloud/fractional-octave-band
en
Reference: [1] Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
https://glossary.acousti.cloud/free-field
en
Reference: [1] Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
https://glossary.acousti.cloud/free_vibration
en
"A vibration resulting from a disturbance of a system and having a period depending solely on the properties of the system." [1]
Reference: [1] Broughton WB. Glossarial Index. In: Acoustic Behavior of Animals. Elsevier; 1963.
https://glossary.acousti.cloud/frequency
en
"The number of cycles or oscillations per unit time in a periodic system." [1]
"The repetition rate of the cycles of an oscillation (e.g. a sound wave). The frequency of audible sound waves is perceived by human ears as the pitch of the sound." [2]
"The rate of repetition of the cycles in a periodic quantity. The reciprocal of the period. The unit is the cycle per second (in Europe, the Hertz: 1 c/s = 1 Hz). By extension applied to recurring quantities even when successive cycles are not identical. In bio-acoustics, there is some tendency to reserve the term for the spectral components of the elementary wave-form alone, a useful expedient for avoiding the all-too-easy confusion of these with other periodicities (such as the tooth-impact rate); periodicity and rate themselves are convenient terms for these latter." [3]
| Synonym | cycles per second | en |
https://glossary.acousti.cloud/frequency_modulation
en
"A periodic change in frequency of a carrier frequency." [1]
Reference: [1] Ewing AW. Arthropod Bioacoustics: Neurobiology and Behaviour. Ithaca, New York: Comstock; 1989.; Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
https://glossary.acousti.cloud/frequency-resolution
en
Reference: [1] Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
https://glossary.acousti.cloud/frequency_response
en
"The sensitivity or output level of a microphone across the range of frequencies it can detect." (from the Acoustic Index User's Guide)
Reference: [1] Jarrett et al. (2025), Journal of Applied Ecology, glossary of key terms. https://doi.org/10.1111/1365-2664.70000
https://glossary.acousti.cloud/frequency_spectrum
en
"The range of frequencies in a sound." [1]
Reference: [1] Ragge DR, Reynolds WJ. The Songs of the Grasshoppers and Crickets of Western Europe. Colchester, Essex: Harley Books; 1998.
https://glossary.acousti.cloud/frequency-weighting
en
Reference: [1] Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
https://glossary.acousti.cloud/fret_call
en
"More precise term for one type of distress call." [1]
Reference: [1] Broughton WB. Glossarial Index. In: Acoustic Behavior of Animals. Elsevier; 1963.
https://glossary.acousti.cloud/full_song
en
"Fully developed adult song under active sex-hormone influence, in contradistinction to subsong, juvenile song." [1]
Reference: [1] Broughton WB. Glossarial Index. In: Acoustic Behavior of Animals. Elsevier; 1963.
https://glossary.acousti.cloud/fundamental
en
The frequency component of a note, usually the lowest, which provides the major proportion of the acoustic energy. Also called the first harmonic.
Reference: [1] Ewing (1989), Glossary of bioacoustic terms, pp. 226–227.
https://glossary.acousti.cloud/fundamental_frequency
en
"The frequency component of a note, usually the lowest, which provides the major proportion of the acoustic energy. Also called the first harmonic." [1]
Reference: [1] Ewing AW. Arthropod Bioacoustics: Neurobiology and Behaviour. Ithaca, New York: Comstock; 1989.; Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
https://glossary.acousti.cloud/gain
en
"Amplification applied to sound received from a microphone during recording. If gain settings are too high, it can lead to clipping if amplitude is increased above the recorder's decibel limit." (from the Acoustic Index User's Guide)
https://glossary.acousti.cloud/GIS
Acronym: GIS
en
Geographical information system
https://glossary.acousti.cloud/geophony
en
"the non-biological natural sounds produced in a given habitat, like wind in the trees or grasses, water in a stream, waves at the ocean shore, or movement of the earth." [1]
"Sounds resulting from natural physical processes including running water, wind in vegetation, and rainfall [2]." (from the Acoustic Index User's Guide)
GFCC, see Greenwood function cepstral coefficients
GIS, see Geographical information system
GMM, see Gaussian mixture model
https://glossary.acousti.cloud/graded-vocalizations
en
Vocalizations that vary along an acoustic continuum, with this variation accompanying changes in the information encoded by the sound signal.
Reference: [1] Mathevon (2023), The Voices of Nature: How and Why Animals Communicate, pp. 305–308.
https://glossary.acousti.cloud/GUI
Acronym: GUI
en
Graphical user interface
https://glossary.acousti.cloud/GFCC
Acronym: GFCC
en
Greenwood function cepstral coefficients
GUI, see Graphical user interface
https://glossary.acousti.cloud/habituation
en
"Upon continual exposure to a signal, an animal will tend to ignore it, and some of the animal’s neurons will cease to fire." [1]
Reference: [1] Page RA, Ryan MJ, Bernal XE. Be loved, be prey, be eaten. 2014.
https://glossary.acousti.cloud/handicap-theory
en
The theory that certain features that are heavy to bear are evidence of the quality of those who bear them; for example, signals that impose a cost to survival.
Reference: [1] Mathevon (2023), The Voices of Nature: How and Why Animals Communicate, pp. 305–308.
https://glossary.acousti.cloud/harmonic
en
"A note whose frequency is an integral multiple of the fundamental frequency. This is only true of an idealized system. In real circumstances the harmonics diverge from the integral values to a varying extent." [1]
Reference: [1] Ewing AW. Arthropod Bioacoustics: Neurobiology and Behaviour. Ithaca, New York: Comstock; 1989.; Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
https://glossary.acousti.cloud/harmonic-frequencies
en
Multiples of the fundamental frequency.
Reference: [1] Mathevon (2023), The Voices of Nature: How and Why Animals Communicate, pp. 305–308.
https://glossary.acousti.cloud/harp
en
"An area of clear membrane in the male fore wings of true crickets and mole-crickets, similar in shape to the musical instrument." [1]
Reference: [1] Ragge DR, Reynolds WJ. The Songs of the Grasshoppers and Crickets of Western Europe. Colchester, Essex: Harley Books; 1998.
https://glossary.acousti.cloud/hearing
en
The ability of organisms to sense sound.
"An insect will be said to hear when it is demonstrably responsive to sound." [1]
"...the only distinction made between hearing and the tactile senses is based on the intensity factor and is quite arbitrary. At the present time no confusion arises in practice because the sensitivity of the auditory organs so far investigated is of a different order from the sensitivity of end-organs usually regarded as tactile. But the distinction is not fundamental, and it can be regarded as certain that further work will demonstrate the existence of end-organs intermediate in sensitivity between “hearing” and “tactile” end-organs. There will then be no justification for attempting a sharp separation." [1]
"Moulton discusses definitions of hearing, primarily in the vertebrate context. Of Pumphrey's definitions, there mentioned, that of 1950 '(an animal hears when it behaves as if it has located a moving object (a sound source) not in contact with it') is rejected as making hearing a definitively directional phenomenon.
His earlier definition ('demonstrable responsiveness to sound) is on the other hand too broad for some workers, and Dijkgraaf incorporates it as only the first of two mandatory criteria, returning to von Buddenbrock for his second, though removing the undue restrictiveness of von Buddenbrock's resonant membranes: (1) demonstrable sensitivity to air- or waterborne sound; together with (2) detection of these stimuli with special detectors primarily used for this purpose. He terms (1) by itself, without (2), merely sound reception; and responsiveness to sound or vibration reaching the animal through the solid substratum, vibration perception.
Though these distinctions between vibration perception, sound perception, and "echter Gehörsinn" remain as artificial as they were in 1937, they are related more realistically to everyday experience than the attempt to treat all that shudders as sound and every reaction to it as a hearing response - and all that glisters as gold. Zoology, indeed, science itself, is founded on the arbitrary subdivision of intergrading series into finite classes, simply as working units for study; in the present context we can recognize the infinite series without having to reject the useful working distinctions between its parts." [2]
https://glossary.acousti.cloud/hemisyllable
en
The sound produced by a to- OR fro- movement of the stridulatory apparatus.
Broughton (1963) took the view that this term should only apply to either of the components of a diplosyllable, preferring the term haplosyllable for syllables where either the to or fro motion was silent. Later authors (e.g. Ragge & Reynolds, 1998) often replace haplosyllable with hemisyllable.
"The sound produced by one unidirectional movement (opening, closing, upward or downward) of the fore wings or hind legs." [1]
Reference: [1] Ragge DR, Reynolds WJ. The Songs of the Grasshoppers and Crickets of Western Europe. Colchester, Essex: Harley Books; 1998.
https://glossary.acousti.cloud/Hertz
en
Hz
"The SI unit of frequency. The number of cycles per second." [1]
Reference: [1] Ewing AW. Arthropod Bioacoustics: Neurobiology and Behaviour. Ithaca, New York: Comstock; 1989.
HFCC, see Human factor cepstral coefficients
https://glossary.acousti.cloud/high-pass_filter
en
"A circuit (electronic or neuronal) which only permits the transmission of high-frequency signals." [1]
Reference: [1] Ewing AW. Arthropod Bioacoustics: Neurobiology and Behaviour. Ithaca, New York: Comstock; 1989.; Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
HMM, see Hidden Markov models
https://glossary.acousti.cloud/homophony
en
"(1) music: opposite of polyphony, i.e. without contrapuntal interplay, melody and harmony moving by and large in the same direction.
(2) linguistics: the quality of being a homophone (a word looking or sounding like another, but with a different meaning, as sun and son)." [1]
Reference: [1] Broughton WB. Glossarial Index. In: Acoustic Behavior of Animals. Elsevier; 1963.
https://glossary.acousti.cloud/honest-communication
en
When a signal carries reliable information about certain characteristics of the sender (e.g., body size). This signal cannot manipulate the receiver.
Reference: [1] Mathevon (2023), The Voices of Nature: How and Why Animals Communicate, pp. 305–308.
https://glossary.acousti.cloud/HFCC
Acronym: HFCC
en
Human factor cepstral coefficients
I, see Sound intensity
IBAC, see International Bioacoustics Council
IBAC, see International Bioacoustics Congress
ICBA, see International Committee for Biological Acoustics
IL, see Intensity level
https://glossary.acousti.cloud/impulse
en
"a brief change of current produced in a circuit. By extension, it could be used for a train of waves (electrical or acoustic) of which it constituted the envelope; but this train would have to be short relative to the interval between it and the next." [1]
Reference: [1] Broughton WB. Glossarial Index. In: Acoustic Behavior of Animals. Elsevier; 1963.
https://glossary.acousti.cloud/impulsion
fr
"strictly = impulse... in my experience, not used in the sense in which pulse is used in English, until recently, and then only in partial equivalence, as translated below from Grand Larousse, 1962:
radiotech: train of very high frequency waves, used notably in radar, which succeed one another periodically in time intervals of some decades of microseconds, and whose duration varies from some hundreds of microseconds to a fraction of a microsecond.
television: sudden variation of amplitude of the modulation, used for transmitting time-base sync. signals.
The second of these definitions is much the same as the British Standard for impulse; the first equates to certain limited kinds of pulse, (as well as to impulses), namely (1) of high-frequency waves; and at the same time (2) of short pulse duration (e.g. less than a millisecond).
It does not, however, specify that the pulse duration shall be short relative to interval or period, and this is where the new definition appears to me to depart from time-honoured practice in the French-language, which, when I was working in France 10 years ago, appeared to have no equivalent whatever to the everyday concept of pulse in the English-speaking world; at that time, impulsion, at least among the physicists I worked with, equated rigorously to impulse, not pulse.
Thus the present situation is that in the electrical context, impulsion can be used for anything from impulses, s.s. to pulse, provided the latter be of inframillisecond duration and of h.f. current. Pulse in acoustics still has no equivalent." [1]
Reference: [1] Broughton WB. Glossarial Index. In: Acoustic Behavior of Animals. Elsevier; 1963.
https://glossary.acousti.cloud/infrasonic
en
"Sounds of a frequency lower than the limit of human hearing (<20 Hz)." (from the Acoustic Index User's Guide)
https://glossary.acousti.cloud/infrasounds
en
Sound waves too low-pitched to be heard by humans (< 20 Hz approximately).
Reference: [1] Mathevon (2023), The Voices of Nature: How and Why Animals Communicate, pp. 305–308.; Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
| Synonym | Infrasound | en |
https://glossary.acousti.cloud/il
Acronym: IL
en
Intensity level: 10 log₁₀(I/Iᵣ) dB.
Reference: [1] Ewing (1989), Glossary of bioacoustic terms, pp. 226–227.
https://glossary.acousti.cloud/international_bioacoustics_congress
Acronym: IBAC
en
International Bioacoustics Congress
https://glossary.acousti.cloud/IBAC
Acronym: IBAC
en
International Bioacoustics Council
https://glossary.acousti.cloud/I.C.B.A.
Acronym: ICBA
en
International Committee for Biological Acoustics.
https://glossary.acousti.cloud/intersyllabic_rhythm
en
| Synonym | zwischensilbe rhythm | de |
https://glossary.acousti.cloud/interval_of_recurrence
en
"lapse of time between the end of one member of a series of more or less irregularly periodic sounds and the beginning of the next. For the concept to have any real meaning in respect of irregular sounds, it must obviously be a mean of a fair sample." [1]
Synonyms: interval of recurrent sounds
Reference: [1] Broughton WB. Glossarial Index. In: Acoustic Behavior of Animals. Elsevier; 1963.
https://glossary.acousti.cloud/intrasyllabic
en
"Within a syllable." [1]
Reference: [1] Ragge DR, Reynolds WJ. The Songs of the Grasshoppers and Crickets of Western Europe. Colchester, Essex: Harley Books; 1998.
IoT, see Internet of Things
https://glossary.acousti.cloud/isobel
en
Line on a map linking points of equal sound intensity.
Iᵣ, see Sound intensity reference level
J, see Joule
https://glossary.acousti.cloud/j
Acronym: J
en
Joule: unit of energy [N m].
Reference: [1] Ewing (1989), Glossary of bioacoustic terms, pp. 226–227.
https://glossary.acousti.cloud/kilohertz
en
kHz
"A unit of frequency: 1 kilohertz = one thousand cycles per second. 1 hertz (Hz) = one cycle per second." [1]
Synonyms: kHz
Reference: [1] Ragge DR, Reynolds WJ. The Songs of the Grasshoppers and Crickets of Western Europe. Colchester, Essex: Harley Books; 1998.
| Synonym | kc/s | en |
https://glossary.acousti.cloud/language
en
Fundamentally, any communication system based on the production of sound signals. However, this term is often reserved for human-articulated language.
Reference: [1] Mathevon (2023), The Voices of Nature: How and Why Animals Communicate, pp. 305–308.
https://glossary.acousti.cloud/lek
en
"An aggregation of males gathered to perform competitive displays to attract and compete for females." [1]
Reference: [1] Jacobs DS, Bastian A. Predator-Prey Interactions: Co-evolution between Bats and their Prey. Springer; 2016.
https://glossary.acousti.cloud/level
en
"of a quantity related to power: the ratio, expressed in decibels, of the magnitude of the quantity to a specified reference magnitude.
Note 1: the word level is frequently used in compound terms such as "intensity level" and "sound pressure level" to relate a magnitude to a common reference magnitude or "zero level".
Note 2: in the absence of any statement to the contrary, the reference magnitude for stating sound pressure levels in air shall be 0.0002 dyne/sq.cm, and that for sound intensity levels 10-16watt/sq.cm." [1]
Reference: [1] Broughton WB. Glossarial Index. In: Acoustic Behavior of Animals. Elsevier; 1963.
LFCC, see Linear-frequency cepstral coefficients
https://glossary.acousti.cloud/LFCC
Acronym: LFCC
en
Linear-frequency cepstral coefficients
https://glossary.acousti.cloud/longitudinal-wave
en
Reference: [1] Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
https://glossary.acousti.cloud/low-pass_filter
en
"A circuit (electronic or neuronal) which only permits the transmission of low-frequency signals." [1]
Reference: [1] Ewing AW. Arthropod Bioacoustics: Neurobiology and Behaviour. Ithaca, New York: Comstock; 1989.; Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
https://glossary.acousti.cloud/machine_learning
en
"The use of algorithms and statistical methods to create computational models which develop or 'learn' through data-based decisions, rather than the pre-set rules of traditional programming." (from the Acoustic Index User's Guide)
https://glossary.acousti.cloud/macrosyllable
en
"In bush-cricket songs with syllables of contrasting duration, a longer (more normal) syllable." [1]
Reference: [1] Ragge DR, Reynolds WJ. The Songs of the Grasshoppers and Crickets of Western Europe. Colchester, Essex: Harley Books; 1998.
https://glossary.acousti.cloud/mathematical-theory-of-communication
en
The theory that all communication is based on the sender-signal-receiver triad, and is subject to noise. The coding of information by the signal can be optimized to meet the constraint imposed by noise. Also known as information theory.
Reference: [1] Mathevon (2023), The Voices of Nature: How and Why Animals Communicate, pp. 305–308.
https://glossary.acousti.cloud/mean-square-sound-pressure
en
Reference: [1] Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
https://glossary.acousti.cloud/mechanism
en
"(1) the apparatus by which sound is produced, e.g. strigil, plectrum, etc.;
(2) the mechanics of its utilization, e.g. friction, buckling, air-streams, etc. without reference to any relationship between this and the character of the sound;
(3) the process of translating the physical and biological properties of the apparatus and its mechanics into the physical parameters of sound (e.g. tooth impacts per second into impulses per second).
These three meanings are quite distinct, and usually "mechanism" only means one of them; but at different times it is used in any or all three senses. This appalling confusion can only be cleared up if we say apparatus when we mean apparatus (see therefore, phonative apparatus, sound-production apparatus); mechanics when we mean mechanics - or possibly just phonation, sound production as they stand; and for sense (3), to avoid repeated circumlocution, use a neologism, for no single word already exists. The best candidate seems to be phonomorphosis, defined as in (3); it is a word neither ugly, complicated, hybrid, nor irregular, and has a clear etymological relationship to its utilization (phonomorphogenesis might indeed better suit the pedant, but its length eliminates it).
If these recommendations be accepted, mechanism itself will remain as an invaluable umbrella term for those contexts where more than one of the three aspects are to be encompassed by a single word." [1]
Reference: [1] Broughton WB. Glossarial Index. In: Acoustic Behavior of Animals. Elsevier; 1963.
https://glossary.acousti.cloud/MFCC
Acronym: MFCC
en
Mel-frequency cepstral coefficients
https://glossary.acousti.cloud/Menzerath-s_law
en
Menzerath's law, or Menzerath–Altmann law (named after Paul Menzerath and Gabriel Altmann), is a linguistic law according to which the increase of the size of a linguistic construct results in a decrease of the size of its constituents, and vice versa.
MFCC, see Mel-frequency cepstral coefficients
https://glossary.acousti.cloud/microsyllable
en
"In bush-cricket songs with syllables of contrasting duration, a shorter syllable, usually lasting less than 10ms." [1]
Reference: [1] Ragge DR, Reynolds WJ. The Songs of the Grasshoppers and Crickets of Western Europe. Colchester, Essex: Harley Books; 1998.
https://glossary.acousti.cloud/mirror
en
"An area of clear membrane in the male fore wings of a bush-cricket or true cricket." [1]
Reference: [1] Ragge DR, Reynolds WJ. The Songs of the Grasshoppers and Crickets of Western Europe. Colchester, Essex: Harley Books; 1998.
https://glossary.acousti.cloud/monaural
en
"deprecated hybrid for one-eared (q.v.) or single eared; properly, either uniaural (in contradistinction to binaural, for hearing); or platyphonic - or at worst, monophonic - (in contradistinction to stereophonic, for reproduction)." [1]
Reference: [1] Broughton WB. Glossarial Index. In: Acoustic Behavior of Animals. Elsevier; 1963.
https://glossary.acousti.cloud/monitor
en
"To listen to a sound picked up by a microphone and reproduced through headphones or loudspeaker, while making a recording of it." [1]
Reference: [1] Ragge DR, Reynolds WJ. The Songs of the Grasshoppers and Crickets of Western Europe. Colchester, Essex: Harley Books; 1998.
https://glossary.acousti.cloud/monopulsate
en
"illegitimate, see unipulsate." [1]
Reference: [1] Broughton WB. Glossarial Index. In: Acoustic Behavior of Animals. Elsevier; 1963.
https://glossary.acousti.cloud/mortons-principle
en
The correspondence between the structure of an acoustic signal and the context of the sender’s emission and motivation. For example, and in general, a dull rumble is more indicative of aggressive intentions, while small, high-pitched, low-intensity calls are typical of a submissive attitude.
Reference: [1] Mathevon (2023), The Voices of Nature: How and Why Animals Communicate, pp. 305–308.
https://glossary.acousti.cloud/motive
en
"(music, preferable to motif): a figure, group of figures, or a phrase which has significance or is otherwise characteristic of a section, phrase, sentence or period. During the succession of the latter, a motive recurs, varied or unvaried, and therefore can give the whole succession - song - a cyclic impression (Sotavalta).
Armstrong uses the term to describe the acoustic individuality of one, or perhaps two or more phrases. Thorpe uses it but little.
The differences are of degree, and not substantial at that." [1]
Reference: [1] Broughton WB. Glossarial Index. In: Acoustic Behavior of Animals. Elsevier; 1963.
| Synonym | motif | en |
https://glossary.acousti.cloud/multipulse
en
"deprecated for multipulsate." [1]
Reference: [1] Broughton WB. Glossarial Index. In: Acoustic Behavior of Animals. Elsevier; 1963.
https://glossary.acousti.cloud/multisyllabic
en
"hybrid for polysyllabic." [1]
Reference: [1] Broughton WB. Glossarial Index. In: Acoustic Behavior of Animals. Elsevier; 1963.
N, see Newton
https://glossary.acousti.cloud/natural_frequency
en
"The frequency of a free vibration... not the same as resonance frequency" [1]
Reference: [1] Broughton WB. Glossarial Index. In: Acoustic Behavior of Animals. Elsevier; 1963.
https://glossary.acousti.cloud/natural_period
en
"period of a free vibration." [1]
Reference: [1] Broughton WB. Glossarial Index. In: Acoustic Behavior of Animals. Elsevier; 1963.
https://glossary.acousti.cloud/natural-selection
en
A process that favors the survival and offspring of individuals best adapted to the environment in which they live. In the context of bioacoustics, natural selection favors communication behaviors and sound signals that increase the survival and/or genetic contribution to the next generation (direct and/or indirect progeny) of the sender and/or receiver.
Reference: [1] Mathevon (2023), The Voices of Nature: How and Why Animals Communicate, pp. 305–308.
https://glossary.acousti.cloud/near_field
en
"The area less than one wavelength from a sound source. In this area pressure and particle velocity are out of phase and sound measurements are unpredictable." [1]
Reference: [1] Ewing AW. Arthropod Bioacoustics: Neurobiology and Behaviour. Ithaca, New York: Comstock; 1989.; Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
https://glossary.acousti.cloud/n
Acronym: N
en
Newton: unit of force [kg m s⁻²].
Reference: [1] Ewing (1989), Glossary of bioacoustic terms, pp. 226–227.
https://glossary.acousti.cloud/node
en
"a point, line or surface of an interference pattern at which the amplitude of the sound pressure (pressure node) or particle velocity (velocity node) is zero (or, in practice, a minimum)." [1]
Reference: [1] Broughton WB. Glossarial Index. In: Acoustic Behavior of Animals. Elsevier; 1963.
https://glossary.acousti.cloud/noise
en
"(1) sound which is undesired by the recipient. Undesired electrical disturbance in a transmission channel or device may also be termed noise, in which case the qualification electrical should be included unless it is self evident.
(2) Sound without regularities, confused sum of many unrelated sounds heard together.
(3)"white noise", the extreme case of (2), in which the sound spectrum contains all frequencies in more or less equal measure." [1]
"Used in ecoacoustics to describe non-target sounds. These could be self-noise from the recording unit, or from aspects of the soundscape such as geophony." (from the Acoustic Index User's Guide)
Reference: [1] Broughton WB. Glossarial Index. In: Acoustic Behavior of Animals. Elsevier; 1963.; Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
https://glossary.acousti.cloud/noise_pollution
en
"Noise pollution refers to the elevation of natural ambient noise levels due to sound-generating human activities, which may have detrimental consequences for humans and animals alike..." [1]
See also: anthropophony
Reference: [1] Slabbekoorn H. Noise pollution. 2019. Available at: https://linkinghub.elsevier.com/retrieve/pii/S0960982219308632.
https://glossary.acousti.cloud/normal_mode
en
"a characteristic distribution of vibration amplitudes, among the parts of a system each part of which is vibrating freely at the same frequency. Complex free vibrations are combinations of these simple normal modes." [1]
Reference: [1] Broughton WB. Glossarial Index. In: Acoustic Behavior of Animals. Elsevier; 1963.
https://glossary.acousti.cloud/note
en
"a. a conventional sign for a tone which indicates its pitch and duration;
b. the tone itself.
N.B. The tone may be, and usually is, complex." [1]
Reference: [1] Broughton WB. Glossarial Index. In: Acoustic Behavior of Animals. Elsevier; 1963.
https://glossary.acousti.cloud/nycthemeral
en
"rhythm with a 24-hour repetition period. The best term of several." [1]
Synonyms: nycthemeral rhythm
Reference: [1] Broughton WB. Glossarial Index. In: Acoustic Behavior of Animals. Elsevier; 1963.
| Synonym | daily rhythm | en |
https://glossary.acousti.cloud/nyquist_frequency
en
"The maximum frequency captured in an audio recording. This is dictated by the recorder settings, being half the sampling rate (see below). So, a recording with a sample rate of 48,000 Hz will have a Nyquist of 24,000 Hz, and only able to capture sounds below that frequency." (from the Acoustic Index User's Guide)
Reference: [1] Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
https://glossary.acousti.cloud/octave-band
en
Reference: [1] Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
https://glossary.acousti.cloud/off-tape_monitoring
en
"Listening to an instant play-back of a recorded sound at the same time as recording it." [1]
Reference: [1] Ragge DR, Reynolds WJ. The Songs of the Grasshoppers and Crickets of Western Europe. Colchester, Essex: Harley Books; 1998.
https://glossary.acousti.cloud/one-third-octave-band
en
Reference: [1] Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
https://glossary.acousti.cloud/open-ended-learner
en
Reference: [1] Lewis et al. (2021), Conservation Biology, glossary of specialist terms. https://doi.org/10.1111/cobi.13465
https://glossary.acousti.cloud/ornithophony
en
"vocalization of birds" [1]
Reference: [1] Divyapriya C, Pramod P. Ornithophony in the soundscape of Anaikatty Hills, Coimbatore, Tamil Nadu, India. 2019. Available at: https://threatenedtaxa.org/index.php/JoTT/issue/view/14471-14630.
https://glossary.acousti.cloud/oscillogram
en
"A visual record of the waveform (and hence amplitude) of a sound on a time scale (obtained from an oscillograph)." [1]
Reference: [1] Ragge DR, Reynolds WJ. The Songs of the Grasshoppers and Crickets of Western Europe. Colchester, Essex: Harley Books; 1998.
https://glossary.acousti.cloud/oscillograph
en
"Equipment for producing an oscillogram." [1]
Reference: [1] Ragge DR, Reynolds WJ. The Songs of the Grasshoppers and Crickets of Western Europe. Colchester, Essex: Harley Books; 1998.
https://glossary.acousti.cloud/oscilloscope
en
"An instrument for displaying a waveform on a screen." [1]
Reference: [1] Ragge DR, Reynolds WJ. The Songs of the Grasshoppers and Crickets of Western Europe. Colchester, Essex: Harley Books; 1998.
https://glossary.acousti.cloud/over-modulation
en
"Recording at too high a level, thus causing a distortion in the recorded sound." [1]
Reference: [1] Ragge DR, Reynolds WJ. The Songs of the Grasshoppers and Crickets of Western Europe. Colchester, Essex: Harley Books; 1998.
https://glossary.acousti.cloud/overtone
en
"a partial whose frequency is higher than, but not necessarily an integral multiple of that of the pure tone to which the pitch would normally be ascribed." [1]
Reference: [1] Broughton WB. Glossarial Index. In: Acoustic Behavior of Animals. Elsevier; 1963.; Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
p, see Sound pressure
Pa, see Pascal
PAM, see passive acoustic monitoring
https://glossary.acousti.cloud/pars_stridens
en
The file portion of the stridulatory device. The plectrum is moved along the file to produce sound.
| Synonym | partes stridentes | la |
https://glossary.acousti.cloud/partial
en
"a pure-tone component of a complex tone." [1]
Reference: [1] Broughton WB. Glossarial Index. In: Acoustic Behavior of Animals. Elsevier; 1963.
https://glossary.acousti.cloud/particle-acceleration
en
Reference: [1] Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
https://glossary.acousti.cloud/particle-displacement
en
Reference: [1] Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
https://glossary.acousti.cloud/particle-velocity
en
Reference: [1] Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
https://glossary.acousti.cloud/pa
Acronym: Pa
en
Pascal: SI unit of pressure; 1 Pa = 1 N m⁻².
Reference: [1] Ewing (1989), Glossary of bioacoustic terms, pp. 226–227.
https://glossary.acousti.cloud/passive_acoustic_monitoring
Acronym: PAM
en
"An ecological monitoring technique using autonomous recording units. Units are left unattended in the field, eliminating the need for human presence." (from the Acoustic Index User's Guide)
Reference: [1] Ross et al. (2023), Functional Ecology, glossary of key terms. https://doi.org/10.1111/1365-2435.14275
https://glossary.acousti.cloud/passive-acoustic-tracking
en
Reference: [1] Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
https://glossary.acousti.cloud/peak-to-peak-sound-pressure
en
Reference: [1] Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
https://glossary.acousti.cloud/peak-to-peak-sound-pressure-level
en
Reference: [1] Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
https://glossary.acousti.cloud/peak-sound-pressure
en
Reference: [1] Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
https://glossary.acousti.cloud/peak-sound-pressure-level
en
Reference: [1] Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
https://glossary.acousti.cloud/period
en
"(1) acoustics: of a periodic quantity: the smallest time-unit for which the quantity repeats itself. By extension, the term period is applied even when successive cycles of oscillation are not identical. The extension means that the term is applied to the time elapsing between corresponding points of two successive members of a series of more or less irregularly periodic sounds. In the last resort, as irregularities increase, the only corresponding points will be the beginnings, hence the ultimate permissible extension of the term for bio-acoustic purposes: lapse of time between two successive homologous members of a series of emissions measured from the beginning of one to the beginning of the other. Clearly, however, the concept of period has no meaning outside of a repetitive context, and for the definition just given to have any meaning it is necessary to take a mean of the time-lapses between successive members in the whole series, or in a fair sample of it.
(2) music, applied to ornithology by Sotavalta: the smallest independent unit of expression: a unit of higher order than the sentence, consisting of one or several sentences which describe the whole expression. Periods are generally coordinated, and separated from each other by a silent interval. A period can be an exact repetition of the preceding period, or be different from it; though it often has a similar structure." [1]
Reference: [1] Broughton WB. Glossarial Index. In: Acoustic Behavior of Animals. Elsevier; 1963.; Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
https://glossary.acousti.cloud/periodicity
en
"neutral term for any count per unit time of a recurrent sound. If frequency be limited in use to spectral components only, periodicity becomes a useful term for all other repetition rates." [1]
Reference: [1] Broughton WB. Glossarial Index. In: Acoustic Behavior of Animals. Elsevier; 1963.
https://glossary.acousti.cloud/periodic_quantity
en
"an oscillatory quantity whose values recur for certain equal increments of time." [1]
Reference: [1] Broughton WB. Glossarial Index. In: Acoustic Behavior of Animals. Elsevier; 1963.
https://glossary.acousti.cloud/phase
en
"the particular point in the cycle that a sinusoidal quantity has reached at the instant of investigation." [1]
Reference: [1] Broughton WB. Glossarial Index. In: Acoustic Behavior of Animals. Elsevier; 1963.
https://glossary.acousti.cloud/phase_difference
en
"(1) between two instantaneous values of the same sinusoidal quantity: the fraction of the whole period that elapses between their occurrence.
(2) between two sinusoidal quantities having the same frequency: the fraction of the whole period that elapses between the occurrence of an instantaneous value of one and the instantaneous value of the other at the corresponding point of the cycle. By natural extension, the concepts of both phase and phase difference are applied to non-sinusoidal periodic quantities, even such as the left and right leg movements in locomotion or stridulation. These are symphasic, or in phase, when there is no phase difference, and the legs are moving in perfect unison; and antiphasic, or fully out of phase, when the phase difference is half a period and the legs are moving in exact antithesis." [1]
Reference: [1] Broughton WB. Glossarial Index. In: Acoustic Behavior of Animals. Elsevier; 1963.
https://glossary.acousti.cloud/phon
en
" a psycho-acoustic of equivalent loudness, the need for which arises from the different sensitivity of the ear to different frequencies. The loudness level in phons of a pure tone is the intensity (in dB above reference level) of a pure tone 1000c/s pure tone assessed (as the modal value of judgments by 'normal' observers) as being equally loud." [1]
Reference: [1] Broughton WB. Glossarial Index. In: Acoustic Behavior of Animals. Elsevier; 1963.
https://glossary.acousti.cloud/phonation
en
"a common definition is the production of sound by voice; which presents few difficulties if discussion is limited to the higher vertebrates. It will be clear, however, from study of this treatise, that there are many other mechanisms in the animal kingdom where vibrating membranes cooperate with resonance cavities of some sort to produce what are essentially vocalized sounds in a manner essentially analogous to that of the vertebrate larynx and its accessories. There is therefore no real reason for limiting the use of the term to mechanisms of the higher vertebrate type. Nevertheless, in deference to common practice, and perhaps common sense, references to what is commonly accepted as vocal production have been entered under phonation, while other mechanisms have on the whole been entered under sound production, stridulation, or strigilation. Some overlapping is inevitable." [1]
Reference: [1] Broughton WB. Glossarial Index. In: Acoustic Behavior of Animals. Elsevier; 1963.
https://glossary.acousti.cloud/phone
en
"umbrella term for a simple vowel or consonant sound." [1]
Reference: [1] Broughton WB. Glossarial Index. In: Acoustic Behavior of Animals. Elsevier; 1963.
https://glossary.acousti.cloud/phonoreception
en
Term proposed by Beer et al 1899 [1] to replace hearing to "eliminate from the study of invertebrate behaviour all reference to human experience" [2].
"This proposal largely failed of its object. On the one hand, it was ignored by the majority of naturalists and morphologists. On the other, where it was adopted by the experimentalists, they often took over the new terms, but used them merely as synonyms for the old. The language was new, but the meaning was the same, and the core of the problem remained untouched. This problem, restated with reference to the subject of this review, is briefly the problem of defining the nature of the evidence which will justify the attribution of a sense of hearing to animals which differ radically from man in their organization and into whose 'minds', if such exist, we have in the nature of things no opportunity of seeing." [2]
"It has in no way cleared up the muddle which inevitably arises when a human observer endeavours to distinguish between phonic and tactile senses in an animal on the basis of his own sensory experience. This confusion is apparent right through the literature up to the present time." [2]
https://glossary.acousti.cloud/phonotaxis
en
"Directional movement in response to sound." [1]
Reference: [1] Ragge DR, Reynolds WJ. The Songs of the Grasshoppers and Crickets of Western Europe. Colchester, Essex: Harley Books; 1998.
https://glossary.acousti.cloud/phonotaxonomy
en
"The taxonomy of animals as indicated by the sounds they produce." [1]
Reference: [1] Ragge DR, Reynolds WJ. The Songs of the Grasshoppers and Crickets of Western Europe. Colchester, Essex: Harley Books; 1998.
https://glossary.acousti.cloud/pitch
en
The property of a sound as determined by the fundamental frequency. Ranges from low to high.
Reference: [1] Mathevon (2023), The Voices of Nature: How and Why Animals Communicate, pp. 305–308.
https://glossary.acousti.cloud/plectrum
en
Part of the stridulatory apparatus that is moved along the file (pars stridens) to produce a sound.
"A scraper on the fore wing of a bush-cricket, true cricket or mole-cricket, which is rubbed against a file on the other fore wing during singing." [1]
Reference: [1] Ragge DR, Reynolds WJ. The Songs of the Grasshoppers and Crickets of Western Europe. Colchester, Essex: Harley Books; 1998.
https://glossary.acousti.cloud/polar-pattern
en
Reference: [1] Jarrett et al. (2025), Journal of Applied Ecology, glossary of key terms. https://doi.org/10.1111/1365-2664.70000
https://glossary.acousti.cloud/polar_plot
en
"A diagram drawn in polar coordinates to show the contours of equal energy surrounding either an emitter or receiver. Used, for example, to illustrate directionality of acoustic receptors." [1]
Reference: [1] Ewing AW. Arthropod Bioacoustics: Neurobiology and Behaviour. Ithaca, New York: Comstock; 1989.
https://glossary.acousti.cloud/power-spectral-density
en
Reference: [1] Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
https://glossary.acousti.cloud/power-spectral-density-percentile
en
Reference: [1] Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
https://glossary.acousti.cloud/power_spectrum
en
"Any complex waveform is composed of discrete sine waves in harmonic series. Fourier analysis is one method of analysing a sound to provide such a series, and a power spectrum is the result of such an analysis where the energy in each of the harmonic components is usually displayed graphically." [1]
Reference: [1] Ewing AW. Arthropod Bioacoustics: Neurobiology and Behaviour. Ithaca, New York: Comstock; 1989.; Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
https://glossary.acousti.cloud/probability-density
en
Reference: [1] Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
https://glossary.acousti.cloud/proclamation_song
en
| Synonym | gewöhnlichegesang | de | |
| Synonym | ordinary song | en |
https://glossary.acousti.cloud/c
Acronym: c
en
Propagation velocity of sound [m s⁻¹]. In air at sea level c ≃ 340 m s⁻¹. In fresh water c ≃ 1430 m s⁻¹. The exact value depends upon pressure, temperature and tonicity; c in sea water is usually taken to be 1500 m s⁻¹.
Reference: [1] Ewing (1989), Glossary of bioacoustic terms, pp. 226–227.; Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
| Synonym | Speed of sound | en |
https://glossary.acousti.cloud/proportional-bandwidth
en
Reference: [1] Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
https://glossary.acousti.cloud/proximal-causes-of-communication
en
Morphological, anatomical, and physiological bases of communication behavior. Proximal causes, in the short term, concern all the mechanisms of production and perception of sound signals.
Reference: [1] Mathevon (2023), The Voices of Nature: How and Why Animals Communicate, pp. 305–308.
https://glossary.acousti.cloud/pulse
en
"A unitary sound normally produced by a single movement of the sound-producing apparatus. It may be monocyclic, as in the sound produced by the wing of some Drosophila species, or polycyclic as in the closing stridulatory wing stroke of crickets." [1]
Reference: [1] Ewing AW. Arthropod Bioacoustics: Neurobiology and Behaviour. Ithaca, New York: Comstock; 1989.
| Synonym | impuls | de |
https://glossary.acousti.cloud/pure-tone
en
Reference: [1] Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
pᵣ, see Sound pressure reference level
Q, see Quality factor
https://glossary.acousti.cloud/q
Acronym: Q
en
Quality factor: a measure of the degree of frequency tuning in an acoustic system. Q = f₀/Δf (3 dB), where f₀ is the resonant frequency of the system.
Reference: [1] Ewing (1989), Glossary of bioacoustic terms, pp. 226–227.
https://glossary.acousti.cloud/quality_factor
en
Q
"A measure of the degree of frequency tuning in an acoustic system." [1]
Reference: [1] Ewing AW. Arthropod Bioacoustics: Neurobiology and Behaviour. Ithaca, New York: Comstock; 1989.
https://glossary.acousti.cloud/quality-index
en
A signal that carries reliable information about the sender because its production is subject to an unavoidable physical constraint that reflects its anatomy, morphology, physiological capabilities, or health (e.g., the lowest fundamental frequency that can be emitted by a mammal is constrained by the size of its vocal cords).
Reference: [1] Mathevon (2023), The Voices of Nature: How and Why Animals Communicate, pp. 305–308.
https://glossary.acousti.cloud/radiated-noise-level
en
Reference: [1] Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
https://glossary.acousti.cloud/reassurance_call
en
| Synonym | anti-alarm call | en |
https://glossary.acousti.cloud/recording_format
en
"The file format for storing a sound recording (e.g., WAV, MP3, FLAC). Each file type has advantages and drawbacks - for example, WAV files are widely used as they are uncompressed and no sound data is lost but they require large amounts of storage space. Compressing files into MP3 reduces the space required but results in data loss [1,2]." (from the Acoustic Index User's Guide)
https://glossary.acousti.cloud/recording_level
en
"The strength of a recorded sound; the setting of the recording equipment control that determines this strength." [1]
Reference: [1] Ragge DR, Reynolds WJ. The Songs of the Grasshoppers and Crickets of Western Europe. Colchester, Essex: Harley Books; 1998.
https://glossary.acousti.cloud/recording_period
en
"The time period when a deployed autonomous recorder is active. The sampling schedule must be chosen to take a representative sample which includes periods of acoustic activity when target ecological activity takes place." (from the Acoustic Index User's Guide)
https://glossary.acousti.cloud/referential-communication
en
The use of signals that designate an environmental feature (such as the presence of a particular predator).
Reference: [1] Mathevon (2023), The Voices of Nature: How and Why Animals Communicate, pp. 305–308.
https://glossary.acousti.cloud/repertoire-size
en
Reference: [1] Lewis et al. (2021), Conservation Biology, glossary of specialist terms. https://doi.org/10.1111/cobi.13465
https://glossary.acousti.cloud/resonant_frequency
en
"The frequency of an oscillating system at which the maximum amplitude of oscillation occurs in response to a driving force." [1]
"The frequency at which resonance occurs in a system. N.B., this and natural frequency are not the same thing, though often used as if synonymous by bio-acousticians... this is the frequency an applied periodic force of minimal value has to have in order to keep the system vibrating. It is clearly higher than the natural frequency." [2]
https://glossary.acousti.cloud/resonant_song
en
"A song with almost pure dominant frequency. If this frequency is sufficiently low, as is common in crickets, the song has a clear musical pitch." [1]
Reference: [1] Ragge DR, Reynolds WJ. The Songs of the Grasshoppers and Crickets of Western Europe. Colchester, Essex: Harley Books; 1998.
https://glossary.acousti.cloud/ritualization
en
The modification of a behavior (aggression, search for food, etc.) that becomes a communication signal by stereotypical simplification.
Reference: [1] Mathevon (2023), The Voices of Nature: How and Why Animals Communicate, pp. 305–308.
https://glossary.acousti.cloud/rivalry_song
en
"The special song produced by two or more males reacting to one another." [1]
Reference: [1] Ragge DR, Reynolds WJ. The Songs of the Grasshoppers and Crickets of Western Europe. Colchester, Essex: Harley Books; 1998.
| Synonym | Chant de rivalité | fr | |
| Synonym | Kilpalaulut | fi | |
| Synonym | Rivalengesang | de |
https://glossary.acousti.cloud/root-mean-square-sound-pressure
en
Reference: [1] Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
https://glossary.acousti.cloud/sampling_rate
en
"The number of times per second which a recording device captures the output from a microphone. For example, 48,000 samples per second is a sampling rate of 48,000 Hz. This determines the resolution of the recording. The higher the sampling rate, the greater the maximum frequency that will be recorded, but note this will be at the Nyquist frequncy (see above), not the sampling rate." (from the Acoustic Index User's Guide)
Reference: [1] Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
| Synonym | Sampling frequency | en |
https://glossary.acousti.cloud/Seewave
en
R package for the analysis and synthesis of sound (seewave).
https://glossary.acousti.cloud/seismonasty
en
Thigmonasty or seismonasty is the nastic response of a plant or fungus to touch or vibration
Synonyms: thigmonasty
https://glossary.acousti.cloud/sensitivity
en
Reference: [1] Jarrett et al. (2025), Journal of Applied Ecology, glossary of key terms. https://doi.org/10.1111/1365-2664.70000
https://glossary.acousti.cloud/sensory_bias
en
"A pre-existing bias in the senses of one sex towards certain stimuli, such bias having evolved in a non-mating context. The bias is then exploited by the other sex in a mating context to obtain more mating opportunities." [1]
Reference: [1] Jacobs DS, Bastian A. Predator-Prey Interactions: Co-evolution between Bats and their Prey. Springer; 2016.
https://glossary.acousti.cloud/sensory-bias
en
A situation in which a receiver’s preexisting sensitivity to a signal may be exploited by the sender. This sensitivity has emerged through evolution for reasons other than communication.
Reference: [1] Mathevon (2023), The Voices of Nature: How and Why Animals Communicate, pp. 305–308.
https://glossary.acousti.cloud/signal
en
Reference: [1] Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
https://glossary.acousti.cloud/signal_to_noise_ratio
Acronym: SNR
en
"The ratio of the energy contained in the parameter of a signal important for communication to that from irrelevant or extraneous sources." [1]
"A measure in decibels (dB) of the strength of the target signal compared with the strength of background noise made by the recorder itself (i.e., self-noise)." (from the Acoustic Index User's Guide)
Reference: [1] Ewing AW. Arthropod Bioacoustics: Neurobiology and Behaviour. Ithaca, New York: Comstock; 1989.; Jarrett et al. (2025), Journal of Applied Ecology, glossary of key terms. https://doi.org/10.1111/1365-2664.70000
| Synonym | SNR | en |
SNR, see signal to noise ratio
https://glossary.acousti.cloud/sonagram
en
"An audiospectrogram produced by a sonagraph." [1]
Reference: [1] Ragge DR, Reynolds WJ. The Songs of the Grasshoppers and Crickets of Western Europe. Colchester, Essex: Harley Books; 1998.
https://glossary.acousti.cloud/sonagraph
en
"A particular kind of audiospectrograph, producing a sonagram." [1]
Reference: [1] Ragge DR, Reynolds WJ. The Songs of the Grasshoppers and Crickets of Western Europe. Colchester, Essex: Harley Books; 1998.
https://glossary.acousti.cloud/song
en
"In bioacoustics this term is used in two main senses: in the broadest sense it is applied to the deliberate acoustic output of animals (or a group of animals) in general, and in a more restricted sense it is applied to the acoustic output of a particular species or individual." [1]
Reference: [1] Ragge DR, Reynolds WJ. The Songs of the Grasshoppers and Crickets of Western Europe. Colchester, Essex: Harley Books; 1998.; Lewis et al. (2021), Conservation Biology, glossary of specialist terms. https://doi.org/10.1111/cobi.13465
| Synonym | chant | fr | |
| Synonym | Laulu | fi | |
| Synonym | Lied | de |
https://glossary.acousti.cloud/song-complexity
en
Reference: [1] Lewis et al. (2021), Conservation Biology, glossary of specialist terms. https://doi.org/10.1111/cobi.13465
https://glossary.acousti.cloud/song-rate
en
Reference: [1] Lewis et al. (2021), Conservation Biology, glossary of specialist terms. https://doi.org/10.1111/cobi.13465
https://glossary.acousti.cloud/soniferous_species
en
"Species capable of deliberately producing sounds." (from the Acoustic Index User's Guide)
https://glossary.acousti.cloud/sound-exposure
en
Reference: [1] Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
https://glossary.acousti.cloud/sound-exposure-level
en
Reference: [1] Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
https://glossary.acousti.cloud/sound-frequency
en
The number of cycles of vibration per second. A low-frequency sound is low-pitched; a high-frequency sound is high-pitched.
Reference: [1] Mathevon (2023), The Voices of Nature: How and Why Animals Communicate, pp. 305–308.
https://glossary.acousti.cloud/i
Acronym: I
en
Sound intensity [W m⁻²]. I = pu = p²/cρ, thus intensity varies with the square of the pressure (I ∝ p²).
Reference: [1] Ewing (1989), Glossary of bioacoustic terms, pp. 226–227.; Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
| Synonym | Acoustic intensity | en |
https://glossary.acousti.cloud/ir
Acronym: Iᵣ
en
Reference level for sound intensity. Usually taken to be 10⁻¹² W m⁻².
Reference: [1] Ewing (1989), Glossary of bioacoustic terms, pp. 226–227.
https://glossary.acousti.cloud/sound_level
en
"Loudness." [1]
Reference: [1] Ragge DR, Reynolds WJ. The Songs of the Grasshoppers and Crickets of Western Europe. Colchester, Essex: Harley Books; 1998.
https://glossary.acousti.cloud/sound-library
en
A collection of sound recordings.
Reference: [1] Mathevon (2023), The Voices of Nature: How and Why Animals Communicate, pp. 305–308.; Ross et al. (2023), Functional Ecology, glossary of key terms. https://doi.org/10.1111/1365-2435.14275
| Synonym | Reference library | en |
https://glossary.acousti.cloud/p
Acronym: p
en
Sound pressure [Pa or N m⁻²].
Reference: [1] Ewing (1989), Glossary of bioacoustic terms, pp. 226–227.; Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
https://glossary.acousti.cloud/sound_pressure_level
Acronym: SPL
en
Sound pressure level measured in decibels relative to a reference level: SPL = 20 log₁₀(p/pᵣ) dB.
Reference: [1] Ewing AW. Arthropod Bioacoustics: Neurobiology and Behaviour. Ithaca, New York: Comstock; 1989.; Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
https://glossary.acousti.cloud/pr
Acronym: pᵣ
en
Sound pressure reference level: 20 μPa (2 × 10⁻⁵ N m⁻²) (sometimes 2 × 10⁻⁴ dynes cm⁻²).
Reference: [1] Ewing (1989), Glossary of bioacoustic terms, pp. 226–227.
https://glossary.acousti.cloud/soundscape
en
"The acoustic environment in a landscape, with biophony, geophony and anthropophony creating patterns of sound that vary over spatial and temporal scales [1,2,3]." (from the Acoustic Index User's Guide)
https://glossary.acousti.cloud/sound_spectrum
en
Reference: [1] Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
| Synonym | audiospectrum | en | |
| Synonym | Spectrum | en |
https://glossary.acousti.cloud/sound_truth
en
"Cataloguing different soundscape characteristics by listening to recordings [1], as opposed to ground truthing, where researchers visit recording sites to conduct aural surveys to identify soundscape characteristics." (from the Acoustic Index User's Guide)
Reference: [1] Holgate B, Maggini R, Fuller S. Mapping ecoacoustic hot spots and moments of biodiversity to inform conservation and urban planning. Ecological Indicators. 2021;126:107627. Available at: https://doi.org/10.1016/j.ecolind.2021.107627.; Bradfer-Lawrence et al. (2023), Methods in Ecology and Evolution, glossary of key ecoacoustic terms. https://doi.org/10.1111/2041-210X.14194
https://glossary.acousti.cloud/sound_wave
en
"Sound is arbitrarily defined as consisting of disturbances of the air of low intensity irrespective of whether or not they are of such a frequency and intensity as to produce the sensation of hearing in a human being. This definition of sound is open to objections. First, it excludes water-borne sounds. ... Secondly, it excludes sounds transmitted through the substrate." [1]
Reference: [1] Pumphrey RJ. Hearing in Insects. Biological Reviews. 1940;15(1):107 - 132. Available at: http://www.blackwell-synergy.com/toc/brv/15/1.; Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
| Synonym | Sound | en |
https://glossary.acousti.cloud/sound-waves
en
Pressure variations that propagate through air or water.
Reference: [1] Mathevon (2023), The Voices of Nature: How and Why Animals Communicate, pp. 305–308.
https://glossary.acousti.cloud/source-filter-theory
en
The theory that the production of sound signals in mammals (and most four-legged vertebrates) is based on an anatomical structure producing a sound wave (the source: larynx in mammals, syrinx in birds), and a system of pipes and cavities modifying this wave (the filter: vocal tract).
Reference: [1] Mathevon (2023), The Voices of Nature: How and Why Animals Communicate, pp. 305–308.
https://glossary.acousti.cloud/source-level
en
Reference: [1] Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
https://glossary.acousti.cloud/spatial-unmasking
en
The ability to locate the origin of a sound signal despite ambient noise when the source of the signal and the source of the noise are not in the same location.
Reference: [1] Mathevon (2023), The Voices of Nature: How and Why Animals Communicate, pp. 305–308.
https://glossary.acousti.cloud/species-classification-algorithm
en
Reference: [1] Ross et al. (2023), Functional Ecology, glossary of key terms. https://doi.org/10.1111/1365-2435.14275
https://glossary.acousti.cloud/spectral-factor
en
Reference: [1] Lewis et al. (2021), Conservation Biology, glossary of specialist terms. https://doi.org/10.1111/cobi.13465
https://glossary.acousti.cloud/spectral-leakage
en
Reference: [1] Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
https://glossary.acousti.cloud/spectrogram
en
"A visual representation of the matrix derived from an FFT, with time on the x-axis, frequency on the y-axis, and amplitude values reflected with a colour or intensity gradient." (from the Acoustic Index User's Guide)
Reference: [1] Ross et al. (2023), Functional Ecology, glossary of key terms. https://doi.org/10.1111/1365-2435.14275; Bradfer-Lawrence et al. (2023), Methods in Ecology and Evolution, glossary of key ecoacoustic terms. https://doi.org/10.1111/2041-210X.14194; Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
SPL, see Sound pressure level
https://glossary.acousti.cloud/static-information
en
Information relating to the stable characteristics of the sender; the constituents of a sender’s vocal signature.
Reference: [1] Mathevon (2023), The Voices of Nature: How and Why Animals Communicate, pp. 305–308.
STDFT, see Short-time discrete Fourier transform
https://glossary.acousti.cloud/stridulation
en
Sound produced by rubbing a series of projections (file; pars stridens) against a plectrum.
"The generation of sound in insects by rubbing legs, wings, or other body parts together." [1]
"Sound production by rubbing one structure against another." [2]
"The act of engaging the file and scraper in the stridulatory area for producing sound." [3]
| Synonym | stridulate | en |
https://glossary.acousti.cloud/stridulatory_area
en
"The area on the tegmina that contains the file and scraper for producing sound. It is located at the basal section of the tegmina." [1]
Reference: [1] Hammelman J. Cricket Radio: Tuning in the Night-singing Insects. Cambridge, Massachusetts: The Belknap Press of Harvard University Press; 2011.
https://glossary.acousti.cloud/stridulatory_field
en
"The area on the tegmina that contains the file and scraper for producing sound. It is located at the basal section of the tegmina." [1]
Reference: [1] Hammelman J. Cricket Radio: Tuning in the Night-singing Insects. Cambridge, Massachusetts: The Belknap Press of Harvard University Press; 2011.
https://glossary.acousti.cloud/stridulatory_organ
en
"The area on the tegmina that contains the file and scraper for producing sound. It is located at the basal section of the tegmina." [1]
Reference: [1] Hammelman J. Cricket Radio: Tuning in the Night-singing Insects. Cambridge, Massachusetts: The Belknap Press of Harvard University Press; 2011.
https://glossary.acousti.cloud/strigilation
en
Sound created by rubbing body parts (more general than stridulation).
https://glossary.acousti.cloud/subjective_soundscape
en
"The acoustic environment as perceived by individual organisms within it [1,2]." (from the Acoustic Index User's Guide)
https://glossary.acousti.cloud/syllable
en
"The sound produced by one to-and-fro movement of the stridulatory apparatus." [1]
"Synonymous with pulse." [2]
| Synonym | Silbe | de | |
| Synonym | Syllabe | fr |
TDSC, see Time domain signal coding
https://glossary.acousti.cloud/technophony
en
"Technophony is a subcomponent of anthropophony referring to machine generated sounds, excluding human speech and music [1]." (from the Acoustic Index User's Guide)
Reference: [1] Mullet TC, Gage SH, Morton JM, Huettmann F. Temporal and spatial variation of a winter soundscape in south-central Alaska. Landscape Ecology. 2016;31(5):1117-1137. Available at: https://doi.org/10.1007/s10980-015-0323-0.; Bradfer-Lawrence et al. (2023), Methods in Ecology and Evolution, glossary of key ecoacoustic terms. https://doi.org/10.1111/2041-210X.14194
https://glossary.acousti.cloud/temporal-factor
en
Reference: [1] Lewis et al. (2021), Conservation Biology, glossary of specialist terms. https://doi.org/10.1111/cobi.13465
https://glossary.acousti.cloud/thigmonasty
en
Thigmonasty or seismonasty is the nastic response of a plant or fungus to touch or vibration
Synonyms: seismonasty
https://glossary.acousti.cloud/timbre
en
The sound of the voice as determined by a combination of many characteristics of sound, including the distribution of energy in the frequency spectrum.
Reference: [1] Mathevon (2023), The Voices of Nature: How and Why Animals Communicate, pp. 305–308.
https://glossary.acousti.cloud/time-difference-of-arrival
en
Reference: [1] Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
https://glossary.acousti.cloud/TDSC
Acronym: TDSC
en
Time domain signal coding
https://glossary.acousti.cloud/tonotopic
en
"In the nervous system; the map-like arrangement of acoustic inter-neurones such that their frequency responses and position are related." [1]
Reference: [1] Ewing AW. Arthropod Bioacoustics: Neurobiology and Behaviour. Ithaca, New York: Comstock; 1989.
https://glossary.acousti.cloud/transient
en
"The sudden alteration of a signal due to the application or removal of a driving force." [1]
Reference: [1] Ewing AW. Arthropod Bioacoustics: Neurobiology and Behaviour. Ithaca, New York: Comstock; 1989.
https://glossary.acousti.cloud/transverse-wave
en
Reference: [1] Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
https://glossary.acousti.cloud/tremulation
en
"Vibrations generated by unspecialized parts of the body (e.g. oscillations of the abdomen) and usually transmitted via legs through the substrate on which the insect is standing."[1]
"Rapid shaking." [2]
https://glossary.acousti.cloud/trill
en
"A sound in which the individual syllables run together to produce a more or less continuous note which may be amplitude-modulated." [1]
Reference: [1] Ewing AW. Arthropod Bioacoustics: Neurobiology and Behaviour. Ithaca, New York: Comstock; 1989.
https://glossary.acousti.cloud/tympanal_aperture
en
"The external opening leading to the tympanum, when it is not completely exposed." [1]
Reference: [1] Ragge DR, Reynolds WJ. The Songs of the Grasshoppers and Crickets of Western Europe. Colchester, Essex: Harley Books; 1998.
https://glossary.acousti.cloud/tympanate
en
"Possessing a tympanic membrane." [1]
Reference: [1] Jacobs DS, Bastian A. Predator-Prey Interactions: Co-evolution between Bats and their Prey. Springer; 2016.
https://glossary.acousti.cloud/tympanic_membrane
en
"A thin membrane that separates the external ear from the middle ear and converts air pressure fluctuations caused by the transmission of sound to vibrations." [1]
Reference: [1] Jacobs DS, Bastian A. Predator-Prey Interactions: Co-evolution between Bats and their Prey. Springer; 2016.
https://glossary.acousti.cloud/tympanum
en
"The membrane forming the outer part of the hearing organ." [1]
Reference: [1] Ragge DR, Reynolds WJ. The Songs of the Grasshoppers and Crickets of Western Europe. Colchester, Essex: Harley Books; 1998.
u, see Vibration velocity
https://glossary.acousti.cloud/ultrasonic
en
"Sounds of a frequency higher than the limit of human hearing (>20 kHz)." (from the Acoustic Index User's Guide)
| ultrasound | en |
https://glossary.acousti.cloud/ultrasound
en
Sound beyond the upper frequency threshold of human hearing. The distinction between sound and ultrasound has no importance biologically except in relation to human hearing.
"Thus the terms 'sonic' and 'ultrasonic' apply to sounds of a frequency audible and inaudible, respectively, to the human ear; but the hearing organs of many insects respond to sound of both types." [1]
"Sound above 20kHz in frequency, and thus inaudible to human ears." [2]
| ultrasonic | en |
https://glossary.acousti.cloud/ultrasounds
en
Sound waves that are too high-pitched to be heard by humans (> 20,000 Hz approximately).
Reference: [1] Mathevon (2023), The Voices of Nature: How and Why Animals Communicate, pp. 305–308.
https://glossary.acousti.cloud/upsweep
en
Reference: [1] Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
uᵣ, see Vibration velocity reference level
https://glossary.acousti.cloud/u
Acronym: u
en
Vibration velocity [m s⁻¹]: u = p/cρ.
Reference: [1] Ewing (1989), Glossary of bioacoustic terms, pp. 226–227.
https://glossary.acousti.cloud/ur
Acronym: uᵣ
en
Vibration velocity reference level: 0.5 × 10⁻⁷ m s⁻¹.
Reference: [1] Ewing (1989), Glossary of bioacoustic terms, pp. 226–227.
https://glossary.acousti.cloud/vocal-learning
en
The mechanisms by which an animal learns to produce a vocalization by imitation.
Reference: [1] Mathevon (2023), The Voices of Nature: How and Why Animals Communicate, pp. 305–308.
https://glossary.acousti.cloud/vocal-plasticity
en
The ability for an individual to rapidly modulate its sound signals.
Reference: [1] Mathevon (2023), The Voices of Nature: How and Why Animals Communicate, pp. 305–308.
https://glossary.acousti.cloud/vocal-repertoire
en
The set of sound signals that an animal can produce.
Reference: [1] Mathevon (2023), The Voices of Nature: How and Why Animals Communicate, pp. 305–308.; Lewis et al. (2021), Conservation Biology, glossary of specialist terms. https://doi.org/10.1111/cobi.13465
| Synonym | Repertoire | en |
https://glossary.acousti.cloud/vocal_sac
en
"The flexible membrane of skin in male frogs used to amplify their mating/advertisement calls." [1]
Reference: [1] Jacobs DS, Bastian A. Predator-Prey Interactions: Co-evolution between Bats and their Prey. Springer; 2016.
https://glossary.acousti.cloud/vocal-signature
en
The information encoded in an audible signal indicating the identity of the sender.
Reference: [1] Mathevon (2023), The Voices of Nature: How and Why Animals Communicate, pp. 305–308.
W, see Watt
https://glossary.acousti.cloud/w
Acronym: W
en
Watt: unit of power [J s⁻¹].
Reference: [1] Ewing (1989), Glossary of bioacoustic terms, pp. 226–227.
https://glossary.acousti.cloud/waveform
en
Reference: [1] Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
https://glossary.acousti.cloud/wavelength
Acronym: λ
en
Wavelength: λ ∝ 1/f; λ = c/f.
Reference: [1] Ewing (1989), Glossary of bioacoustic terms, pp. 226–227.; Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
https://glossary.acousti.cloud/white_noise
en
"[noise in which] the sound spectrum contains all frequencies in more or less equal measure." [1]
Reference: [1] Broughton WB. Glossarial Index. In: Acoustic Behavior of Animals. Elsevier; 1963.
https://glossary.acousti.cloud/window-function
en
Reference: [1] Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
https://glossary.acousti.cloud/withdrawal-of-learning
en
Reference: [1] Lewis et al. (2021), Conservation Biology, glossary of specialist terms. https://doi.org/10.1111/cobi.13465
WSN, see Wireless sensor network
https://glossary.acousti.cloud/zero-padding
en
Reference: [1] Erbe et al. (2022), Exploring Animal Behavior Through Sound, Terms and Definitions. https://doi.org/10.1007/978-3-030-97540-1_4
https://glossary.acousti.cloud/Zipf-s_law
en
Zipf's law was originally formulated in terms of quantitative linguistics, stating that given some corpus of natural language utterances, the frequency of any word is inversely proportional to its rank in the frequency table.
To cite this website:
Ed Baker (2026) Bioacoustics & Ecoacoustics Glossary (https://glossary.acousti.cloud/). Accessed on October 6, 2026, 10:23 pm.