3. (Zoöl.) See Acorn- shell.
(A"corn cup) The involucre or cup in which the acorn is fixed.
1. Furnished or loaded with acorns.
2. Fed or filled with acorns. [R.] Shak.
(A"corn-shell`) n. (Zoöl.) One of the sessile cirripeds; a barnacle of the genus Balanus.
(A*cos"mism) n. [Gr. 'a priv. + world.] A denial of the existence of the universe as distinct
(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) 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) 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
(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.
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
(A*cous"tic) 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.
(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) 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,
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.