Main Entry: acous·tic

Pronunciation: \ə-ˈküs-tik\

Variant(s): or acous·ti·cal \-ti-kəl\

Function: adjective

Etymology: Greek akoustikos of hearing, from akouein to hear — more at hear

Date: 1605

1 : of or relating to the sense or organs of hearing, to sound, or to the science of sounds <acoustic apparatus of the ear> <acoustic energy>: as a : deadening or absorbing sound <acoustic tile> b : operated by or utilizing sound waves
2 : of, relating to, or being a musical instrument whose sound is not electronically modified

— acous·ti·cal·ly \-k(ə-)lē\ adverb