acous-, acou-, acouo-, acoustico-, acouto-, acousti-, -acousia, -acousis, -acoustical, acu-, -acusis-, -acusia

(Greek: akoustikos, to hear, hearing; to listen, listening)

electroacoustics (s) (noun) (a plural form that functions as a singular)
The science which deals with sound and its relationship to electricity: "Loudspeakers and microphones are examples of the applications of electroacoustics."

"Electroacoustics is also used in sound broadcasting, sound recording and reproduction; as well as, ultrasonic flaw detection and technology."

electron acoustic microscopy (s) (noun), electron acoustic microscopies (pl)
A technique for producing images showing the thermal (heat) and elastic variations in the properties of an object: "The process of electron acoustic microscopy consists of an electron beam that generates ultrasonic waves in a specimen which are detected by a piezoelectric transducer whose output controls the brightness of a spot sweeping a cathode-ray tube in synchronism with the electron beam."
engineering acoustics (pl) (noun) (a plural form functioning as a singular)
The field of science that deals with the production, detection, and control of sound by electrical devices: "Some engineering acoustics include the study, design, and construction of such instruments as microphones, loudspeakers, sound recorders and reproducers, and public address systems."
entacoustic (adjective), more entacoustic, most entacoustic
Referring to subjective sensations of hearing that originate within or near one's ear or ears: "The sounds of waves crashing against the side of his boat were the most entacoustic sounds the fisherman experienced as he lay on the bottom of his disabled fishing vessel."
geoacoustical (adjective), more geoacoustical, most geoacoustical
Descriptive of the equipment a person can use to detect compositions of layers under the surface of the earth: "The mining industry found that geoacoustical equipment was very useful in their search for precious metals."
geoacoustics (s) (noun) (a plural form that functions as a singular)
The use of echo-ranging devices with low-frequency seismographic waves transmitted several miles into the earth's crust to determine the composition and characteristics of the area: "Sam's cousin, Hanson, is a scientist who has developed unique techniques for the use of geoacoustics in his research about the minerals that exist below the surface of the ground."
hypacusis (s) (noun), hypacuses (pl)
1. A hearing impairment consisting of an inadequate reception of sounds to the ears or partial deafness: "The doctor told Etta that she had hypacusis which is why she was having so much trouble hearing what the speakers on her TV were saying and finding it necessary to ask people to repeat what they said because she simply could not hear every thing that was spoken."
2. Etymology: from Greek hypo-, "under, less than" + Greek akousis, "hearing".
hyperacusia (s) (noun), hyperacusias (pl)
1. Abnormally sharp and loud hearing, sometimes resulting in pain even when only moderately loud sounds are in the area of the subject: "Brett had been diagnosed with hyperacusia which made his job of monitoring crowds at band concerts too difficult for him to tolerate any more because the sounds of the crowds and the bands were too painful for his ears."

"Deafness is not the only danger of noise exposure of hyperacusia; in fact, the stress causes some 45,000 fatal heart attacks a year in the developing world, according to researcher Dieter Schwela of the Stockholm Environment Institute."

—Compiled from information located in
"Noise" by Jonathon Keats; Discover magazine;
June, 2014; page 74.
2. Increased sharpness of hearing or a condition that exists when sounds are perceived as abnormally loud: "Although Caroline always wanted to attend a live concert with her favorite band, she was advised not to do so because of the hyperacusia in her ears which would make going to the concert a terribly painful experience."
hyperacusis (s) (noun), hyperacuses (pl)
An excessive sharpness during the hearing process that causes pain: "Hyperacusis causes pain because of an over sensitivity to certain normal sounds that can result from emotional or because of physical reasons."
hypoacusia (s) (noun), hypoacusias (pl)
Any sound that is below or less than the comfortable level of hearing: "The hypoacusia in the auditorium was so bad that an amplification system was required for all events."
hypoacusis (s) (noun), hypoacuses (pl)
Reduced or slightly impaired hearing which often involves neurosensory organs: "In the early 1930's, when Bill realized that he was experiencing hypoacusis, he could not afford a hearing aid; so, he put a small button on a string, put the button in his ear and the string in his pocket and, as a result, Bill noticed that people automatically spoke louder and so he had no trouble understanding them."
ion-acoustic wave
A longitudinal compression wave in the ion density of a plasma which can occur at high electron temperatures and low frequencies, and is caused by a combination of ion inertia and electron pressure.
isacoustic (adjective), more isacoustic, most isacoustic
1. Applied to a curve passing through those points (in a theater, concert-room, etc.) at which a speaker or performer may be heard equally well: "Terry always chooses the most isacoustic seat in the auditorium so she can hear the speakers."
2. A reference to the equal intensity of sound: "The natural acoustics of the outdoor amphitheater provided balanced isacoustic music."
3. In seismology, applied to a line (imaginary or on a map) connecting places where an equal percentage of observers hear the sound of an earthquake: "The seismologists at three universities realized that their institutions were situated on an isacoustic line meaning that they each could hear quakes equally well when they occur."
micracoustic, microacoustic (adjective), more micracoustic, most micracoustic
A reference to an instrument that can be used to magnify small sounds so they can be heard: "There are micracoustic, or microacoustic, devices which can make otherwise impossible sounds audible."
odynacusis (s) (noun) (no plural)
Hypersensitiveness of the ears that result in some noises causing pain: "Darrell's headaches and pain in his ears appeared to be the result of odynacusis which is especially noticeable when he is listening to a radio that is turned up to its higher volume."

If you would like to take a self-scoring quiz over many of the words in this unit, then click on this Hearing Quiz link so you can see how much you know about some of these “acous-, acou-” words.

Related "hear, hearing; listen, listening" units: audio-; ausculto-.