indigo

a. Having the color of, pertaining to, or derived from, indigo. [ 1913 Webster ]

Indigo berry (Bot.), the fruit of the West Indian shrub Randia aculeata, used as a blue dye. --
Indigo bird (Zool.), 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 Indigofera tinctoria, or common indigo plant, the Indigofera Anil, a larger species, and the Indigofera 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 (Zool.), 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. [ 1913 Webster ]

‖n. [ NL., from E. indigo + L. ferre to bear. ] (Bot.) A genus of leguminous plants (family Leguminosae) having many species, mostly in tropical countries, several of them yielding indigo, esp. Indigofera tinctoria, Indigofera suffroticosa, and Indigofera Anil. [ 1913 Webster ]

n. [ Indigo + -gen. ] [ 1913 Webster ]

1. (Chem.) See Indigo white, under Indigo. [ 1913 Webster ]

2. (Physiol. Chem.) Same as Indican, 2. [ 1913 Webster ]

n. [ Indigo + -meter. ] An instrument for ascertaining the strength of an indigo solution, as in volumetric analysis. Ure. [ 1913 Webster ]

n. The art or method of determining the coloring power of indigo. [ 1913 Webster ]

a. [ Cf. F. indigotique. ] (Chem.) Pertaining to, or derived from, indigo; as, indigotic acid, which is also called anilic or nitrosalicylic acid. [ 1913 Webster ]