ETYM French indigo, Spanish indigo, indico, Latin indicum indigo, from Indicus Indian. Related to Indian.
1. A blue-violet color.
2. Deciduous subshrub of southeastern Asia having pinnate leaves and clusters of red or purple flowers; a source of indigo dye; SYN. indigo plant, Indigofera tinctoria.
3. Dark blue color and dye; plant yielding it.
4. Violet-blue vegetable dye obtained from plants of the genus Indigofera, family Leguminosae, but now replaced by a synthetic product. It was once a major export crop of India.

Having the color of, pertaining to, or derived from, indigo.