a. [ Pref. ultra- + violet. ] (Physics) Lying outside the visible spectrum at its blue-violet end; -- said of light more refrangible (i. e. having a shorter wavelength) than the extreme violet rays of the visible spectrum. Electromagnetic radiation with wavelengths shorter than those of ultrviolet light are not usually considered as light waves, but are classified differently. The ultraviolet region of the electromagnetic spectrum is generally considered as comprising those electromagnetic emissions with wavelengths lying between those of visible light and those of X-rays, i. e. between 4000 Angstroms and 100 Angstroms. [ 1913 Webster +PJC ]

n. [ F. violette a violet (cf. violet violet-colored), dim. of OF. viole a violet, L. viola; akin to Gr. &unr_;. Cf. Iodine. ] 1. (Bot.) Any plant or flower of the genus Viola, of many species. The violets are generally low, herbaceous plants, and the flowers of many of the species are blue, while others are white or yellow, or of several colors, as the pansy (Viola tricolor). [ 1913 Webster ]

☞ The cultivated sweet violet is Viola odorata of Europe. The common blue violet of the eastern United States is Viola cucullata; the sand, or bird-foot, violet is Viola pedata. [ 1913 Webster ]

2. The color of a violet, or that part of the spectrum farthest from red. It is the most refrangible part of the spectrum. [ 1913 Webster ]

3. In art, a color produced by a combination of red and blue in equal proportions; a bluish purple color. Mollett. [ 1913 Webster ]

4. (Zool.) Any one of numerous species of small violet-colored butterflies belonging to Lycaena, or Rusticus, and allied genera. [ 1913 Webster ]

[ 1913 Webster ]

Corn violet. See under Corn. --
Dame's violet. (Bot.) See Damewort. --
Dogtooth violet. (Bot.) See under Dogtooth. --
Water violet (Bot.), an aquatic European herb (Hottonia palustris) with pale purplish flowers and pinnatifid leaves. [ 1913 Webster ]

a. [ Cf. F. violet. See Violet, n. ] Dark blue, inclining to red; bluish purple; having a color produced by red and blue combined. [ 1913 Webster ]

Violet shell (Zool.), any species of Ianthina; -- called also violet snail. See Ianthina. --
Violet wood, a name given to several kinds of hard purplish or reddish woods, as king wood, myall wood, and the wood of the Andira violacea, a tree of Guiana. [ 1913 Webster ]

n. Any tropical humming bird of the genus Petasophora, having violet or purplish ear tufts. [ Webster 1913 Suppl. ]

n. (Zool.) A very handsome American butterfly (Polygonia interrogationis). Its wings are mottled with various shades of red and brown and have violet tips. [ 1913 Webster ]

(Bot.) See under Violet. [ 1913 Webster ]