adj. & n.
--adj.
1. relating to sound or the sense of hearing.
2 (of a musical instrument, gramophone, or recording) not having electrical amplification (acoustic guitar).
3 (of building materials) used for soundproofing or modifying sound.
4 Mil. (of a mine) that can be exploded by sound waves transmitted under water.
--n.
1. (usu. in pl.) the properties or qualities (esp. of a room or hall etc.) in transmitting sound (good acoustics; a poor acoustic).
2 (in pl.; usu. treated as sing.) the science of sound (acoustics is not widely taught).
Phrases and idioms:
acoustic coupler Computing a modem which converts digital signals into audible signals and vice versa, so that the former can be transmitted and received over telephone lines.
Derivatives:
acoustical adj. acoustically adv.
Etymology: Gk akoustikos f. akouo hear