Part 69

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.

Ac*quaint" (&?;), a. [OF. acoint. See Acquaint, v. t.] Acquainted. [Obs.]

Ac*quaint", v. t. [imp. & p. p. Acquainted; p. pr. & vb. n. Acquainting.] [OE. aqueinten, acointen, OF. acointier, LL. adcognitare, fr. L. ad + cognitus, p. p. of cognoscere to know; con- + noscere to know. See Quaint, Know.] 1. To furnish or give experimental knowledge of; to make (one) to know; to make familiar; -- followed by with.

Before a man can speak on any subject, it is necessary to be acquainted with it. Locke.

A man of sorrows and acquainted with grief. Isa. liii. 3.

2. To communicate notice to; to inform; to make cognizant; -- followed by with (formerly, also, by of), or by that, introducing the intelligence; as, to acquaint a friend with the particulars of an act.

Acquaint her here of my son Paris' love. Shak.

I must acquaint you that I have received New dated letters from Northumberland. Shak.

3. To familiarize; to accustom. [Obs.] Evelyn.

To be acquainted with, to be possessed of personal knowledge of; to be cognizant of; to be more or less familiar with; to be on terms of social intercourse with.

Syn. -- To inform; apprise; communicate; advise.

Ac*quaint"a*ble (&?;), a. [Cf. OF. acointable]. Easy to be acquainted with; affable. [Obs.] Rom. of R.