Achromatic lens (Opt.), a lens composed usually of two separate lenses, a convex and concave, of substances having different refractive and dispersive powers, as crown and flint glass, with the curvatures so adjusted that the chromatic aberration produced by the one is corrected by other, and light emerges from the compound lens undecomposed. -- Achromatic prism. See Prism. -- Achromatic telescope, or microscope, one in which the chromatic aberration is corrected, usually by means of a compound or achromatic object glass, and which gives images free from extraneous color.
Ach`ro*mat"ic*al*ly (&?;), adv. In an achromatic manner.
Ach`ro*ma*tic"i*ty (&?;), n. Achromatism.
A*chro"ma*tin (&?;), n. (Biol.) Tissue which is not stained by fluid dyes. W. Flemming.
A*chro"ma*tism (&?;), n. [Cf. F. achromatisme.] The state or quality of being achromatic; as, the achromatism of a lens; achromaticity. Nichol.
A*chro`ma*ti*za"tion (&?;), n. [Cf. F. achromatisation.] The act or process of achromatizing.
A*chro"ma*tize (&?;), v. t. [imp. & p. p. Achromatized (&?;); p. pr. & vb. n. Achromatizing (&?;).] [Gr. 'a priv. + &?; color.] To deprive of color; to make achromatic.
A*chro"ma*top"sy (&?;), n. [Gr. 'a priv. + &?; color + &?; sight.] Color blindness; inability to distinguish colors; Daltonism.
A*chron"ic (&?;), a. See Acronyc.
Ach`ro*ö*dex"trin (&?;), n. [Gr. &?; colorless + E. dextrin.] (Physiol. Chem.) Dextrin not colorable by iodine. See Dextrin.
Ach"ro*ous (&?;), a. [Gr. &?;; 'a priv. + &?; color.] Colorless; achromatic.
A*chy"lous (&?;), a. [Gr. &?; without juice.] (Physiol.) Without chyle.
A*chy"mous (&?;), a. [Gr. &?; without juice.] (Physiol.) Without chyme.
||A*cic"u*la (&?;), n.; pl. Aciculæ (&?;). [L., a small needle, dimin. of acus needle.] (Nat. Hist.) One of the needlelike or bristlelike spines or prickles of some animals and plants; also, a needlelike crystal.
A*cic"u*lar (&?;), a. Needle-shaped; slender like a needle or bristle, as some leaves or crystals; also, having sharp points like needles.
A*cic"u*lar*ly, adv..
{ A*cic"u*late (&?;), A*cic"u*la"ted (&?;) } a. (Nat. Hist.) (a) Furnished with aciculæ. (b) Acicular. (c) Marked with fine irregular streaks as if scratched by a needle. Lindley.
A*cic"u*li*form (&?;), a. [L. acicula needle + -form.] Needle-shaped; acicular.
A*cic"u*lite (&?;), n. (Min.) Needle ore. Brande & C.
Ac"id (&?;), a. [L. acidus sour, fr. the root ak to be sharp: cf. F. acide. Cf. Acute.] 1. Sour, sharp, or biting to the taste; tart; having the taste of vinegar: as, acid fruits or liquors. Also fig.: Sour- tempered.
He was stern and his face as acid as ever.
A. Trollope.