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," which probably is from copulative prefix a- (see a- (3)) + koein "to mark, perceive, hear" (from PIE root *kous- "to hear," which is also the presumed 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 distinguished from electric) is attested by 1958. Related: Acoustical; acoustically.
