Ach·ilÏle¶an (#), a. Resembling Achilles, the hero of the Iliad; invincible.
AÏchil¶les' ten¶don (#), n. [L. Achillis tendo.] (Anat.) The strong tendon formed of the united tendons of the large muscles in the calf of the leg, an inserted into the bone of the heel; Ð so called from the mythological account of Achilles being held by the heel when dipped in the River Styx.
AÏchi¶lous (#), a. [Gr. ? priv. + ? lip.] (Bot.) Without a lip.
Ach¶ing (#), a. That aches; continuously painful. See Ache. Ð Ach¶ingÏly, adv. The aching heart, the aching head. Longfellow. Ø A·chiÏo¶te (#), n. [Sp. achiote, fr. Indian achiotl.] Seeds of the annotto tree; also, the coloring matter, annotto. AÏchlam¶yÏdate (#), a. [Gr. ? priv. + ?. ?. a short cloak.] (Zo”l.) Not possessing a mantle; Ð said of certain gastropods.
Ach·laÏmyd¶eÏous (#), a. (Bot.) Naked; having no floral envelope, neither calyx nor corolla.
Ø AÏcho¶liÏa (#), n. [NL., from Gr. ?; ? priv. + ? bile.] (Med.) Deficiency or want of bile.
Ach·roÏmat¶ic (#), a. [Gr. ? colorless; ? priv. + ?, ?, color: cf. F. achromatique.] 1. (Opt.) Free from color; transmitting light without decomposing it into its primary colors. 2. (Biol.) Uncolored; not absorbing color from a fluid; Ð said of tissue. 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. Ð Achromatic prism. See Prism, Ð 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·roÏmat¶icÏalÏly (#), adv. In an achromatic manner.
AÏchro¶maÏtin (#), n. (Biol.) Tissue which is not stained by fluid dyes. W. Flemming.
AÏchro¶maÏtism (#), n. [Cf. F. achromatisme.] The state or quality of being achromatic; as, the achromatism of a lens; achromaticity. Nichol.
AÏchro·maÏtiÏza¶tion (#), n. [Cf. F. achromatisation.] The act or process of achromatizing.
AÏchro¶maÏtize (#), v. t. [imp. & p. p. Achromatized (#); p. pr. & vb. n. Achromatizing (#).] [Gr. ? priv. + ? color.] To deprive of color; to make achromatic.