- acoustic
- c.1600, from Fr. acoustique, from Gk. akoustikos "pertaining to hearing," from akoustos "heard, audible," from akouein "to hear," from copulative prefix a- + koein "to mark, perceive, hear," from PIE base *(s)keu- "to notice, observe" (see caveat). Acoustic guitar (as opposed to electric) attested by 1958.