A"corn-shell` (&?;), n. (Zoöl.) One of the sessile cirripeds; a barnacle of the genus Balanus. See Barnacle.
A*cos"mism (&?;), n. [Gr. 'a priv. + &?; world.] A denial of the existence of the universe as distinct from God.
A*cos"mist (&?;), n. [See Acosmism.] One who denies the existence of the universe, or of a universe as distinct from God. G. H. Lewes.
A*cot`y*le"don (#; 277), n. [Gr. 'a priv. + &?; anything cup-shaped. See Cotyledon.] (Bot.) A plant which has no cotyledons, as the dodder and all flowerless plants.
A*cot`y*led"on*ous (#; 277), a. Having no seed lobes, as the dodder; also applied to plants which have no true seeds, as ferns, mosses, etc.
A*cou"chy (&?;), n. [F. acouchi, from the native name Guiana.] (Zoöl.) A small species of agouti (Dasyprocta acouchy).
A*cou"me*ter (&?;), n. [Gr. &?; to hear + -meter.] (Physics.) An instrument for measuring the acuteness of the sense of hearing. Itard.
A*cou"me*try (&?;), n. [Gr. &?; to hear + -metry.] The measuring of the power or extent of hearing.
A*cous"tic (#; 277), a. [F. acoustique, Gr. &?; relating to hearing, fr. &?; to hear.] Pertaining to the sense of hearing, the organs of hearing, or the science of sounds; auditory.
Acoustic duct, the auditory duct, or external passage of the ear. -- Acoustic telegraph, a telegraph making audible signals; a telephone. -- Acoustic vessels, brazen tubes or vessels, shaped like a bell, used in ancient theaters to propel the voices of the actors, so as to render them audible to a great distance.
A*cous"tic, n. A medicine or agent to assist hearing.
A*cous"tic*al (&?;), a. Of or pertaining to acoustics.
A*cous"tic*al*ly (&?;), adv. In relation to sound or to hearing. Tyndall.
Ac`ous*ti"cian (&?;), n. One versed in acoustics. Tyndall.
A*cous"tics (#; 277), n. [Names of sciences in -ics, as, acoustics, mathematics, etc., are usually treated as singular. See -ics.] (Physics.) 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.
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.