audio-

Collins Concise English Dictionary © HarperCollins Publishers::

audio- combining_form

1. indicating hearing or sound: audiometer, audiovisual

Etymology: from Latin audīre to hear

WordReference Random House Learner's Dictionary of American English © 2025

au•di•o /ˈɔdiˌoʊ/   adj. 

[before a noun]
1. Electronics, Sound Reproduction of, relating to, or used in the sending, receiving, or producing of sound:
   audio equipment.

n. [uncountable]

2. Radio and Television the elements of television that deal with sound:
   The audio was OK but there was no picture.
3. Sound Reproduction the job or field of study concerned with sound recording, transmission, reception, and reproduction.

See -aud-.

WordReference Random House Unabridged Dictionary of American English © 2025

au•di•o  (ô′dē ō′), adj. 

1. Electronics, Sound Reproduction designating an electronic apparatus using audio frequencies:
   audio amplifier.
2. Electronics, Sound Reproduction of, pertaining to, or employed in the transmission, reception, or reproduction of sound.
3. Electronics, Sound Reproduction of or pertaining to frequencies or signals in the audible range.

n. 

4. [Television.]
   • Radio and Television the audio elements of television (distinguished from video).
   • Radio and Television the circuits in a receiver for reproducing sound.
   • Radio and Television the audio part of a television broadcast.
5. Sound Reproduction the field of sound recording, transmission, reception, and reproduction.

• independent use of audio- 1920–25

audio-, 

1. Sound Reproduction a combining form used in the formation of compound words, with the meanings: "sound within the range of human hearing'' (audiometer);
   "hearing'' (audiology);
   "sound reproduction'' (audiophile).

• Latin audī- (stem of audīre to hear) +-o-