Crossword Dictionary

What's The Definition Of Indigo?

\In"di*go\, n.; pl. {Indigoes}. [F. indigo, Sp. indigo, indico, L. indicum indigo, fr. Indicus Indian. See {Indian}.] 1. A kind of deep blue, one of the seven prismatic colors. 2. (Chem.) A blue dyestuff obtained from several plants belonging to very different genera and orders; as, the woad, {Isatis tinctoria}, {Indigofera tinctoria}, {I. Anil}, {Nereum tinctorium}, etc. It is a dark blue earthy substance, tasteless and odorless, with a copper-violet luster when rubbed. Indigo does not exist in the plants as such, but is obtained by decomposition of the glycoside indican. Note: Commercial indigo contains the essential coloring principle indigo blue or indigotine, with several other dyes; as, indigo red, indigo brown, etc., and various impurities. Indigo is insoluble in ordinary reagents, with the exception of strong sulphuric acid. {Chinese indigo} (Bot.), {Isatis indigotica}, a kind of woad. {Wild indigo} (Bot.), the American herb {Baptisia tinctoria} which yields a poor quality of indigo, as do several other species of the same genus.
\In"di*go\, a. Having the color of, pertaining to, or derived from, indigo. {Indigo berry} (Bot.), the fruit of the West Indian shrub {Randia aculeata}, used as a blue dye. {Indigo bird} (Zo["o]l.), a small North American finch ({Cyanospiza cyanea}). The male is indigo blue in color. Called also {indigo bunting}. {Indigo blue}. (a) The essential coloring material of commercial indigo, from which it is obtained as a dark blue earthy powder, with a reddish luster, {C16H10N2O2}, which may be crystallized by sublimation. Indigo blue is also made from artificial amido cinnamic acid, and from artificial isatine; and these methods are of great commercial importance. Called also {indigotin}. (b) A dark, dull blue color like the indigo of commerce. {Indigo brown} (Chem.), a brown resinous substance found in crude indigo. {Indigo copper} (Min.), covellite. {Indigo green}, a green obtained from indigo. {Indigo plant} (Bot.), a leguminous plant of several species (genus {Indigofera}), from which indigo is prepared. The different varieties are natives of Asia, Africa, and America. Several species are cultivated, of which the most important are the {I. tinctoria}, or common indigo plant, the {I. Anil}, a larger species, and the {I. disperma}. {Indigo purple}, a purple obtained from indigo. {Indigo red}, a dyestuff, isomeric with indigo blue, obtained from crude indigo as a dark brown amorphous powder. {Indigo snake} (Zo["o]l.), the gopher snake. {Indigo white}, a white crystalline powder obtained by reduction from indigo blue, and by oxidation easily changed back to it; -- called also {indigogen}. {Indigo yellow}, a substance obtained from indigo.