Indigo blue Meaning, Definition & Usage

Definitions

1. . (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.