acoustic (adj.)

c. 1600, "pertaining to hearing or sound," from French acoustique, from Latinized form of Greek akoustikos "pertaining to hearing," from akoustos "heard, audible," verbal adjective from akouein "to hear," probably from copulative prefix a- (see a- (3)) + koein "to mark, perceive, hear," from PIE root *kous- "to hear" (also source of English hear).

In reference to material meant to deaden sound, 1924. Of sound reproduced mechanically (rather than electrically) from 1932 in reference to gramophone players; acoustic guitar (as opposed to electric) attested by 1958. Related: Acoustical; acoustically.

Others are reading

Definitions of acoustic from WordNet
acoustic (n.)
a remedy for hearing loss or deafness;
acoustic (adj.)
of or relating to the science of acoustics;
acoustic properties of a hall
Synonyms: acoustical