ACOUSTICAL
A*cous"tic*al, a.

Defn: Of or pertaining to acoustics.

ACOUSTICALLY
A*cous"tic*al*ly, adv.

Defn: In relation to sound or to hearing. Tyndall.

ACOUSTICIAN
Ac`ous*ti"cian, n.

Defn: One versed in acoustics. Tyndall.

ACOUSTICS A*cous"tics (#; 277), n. Etym: [Names of sciences in -ics, as, acoustics, mathematics, etc., are usually treated as singular. See - ics.] (Physics.)

Defn: The science of sounds, teaching their nature, phenomena, and
laws.
Acoustics, then, or the science of sound, is a very considerable
branch of physics. Sir J. Herschel.

Note: The science is, by some writers, divided, into diacoustics, which explains the properties of sounds coming directly from the ear; and catacoustica, which treats of reflected sounds or echoes.

ACQUAINT
Ac*quaint", a. Etym: [OF. acoint. See Acquaint, v. t.]