- a blue dye obtained from various plants, especially of the genus Indigofera, or manufactured synthetically.
- indigo blue (def. 2).
- any of numerous hairy plants belonging to the genus Indigofera, of the legume family, having pinnate leaves and clusters of usually red or purple flowers.
- a color ranging from a deep violet blue to a dark, grayish blue.
- of the color indigo.
- a blue vat dye originally obtained from plants but now made synthetically
- any of various tropical plants of the leguminous genus Indigofera, such as the anil, that yield this dye
- any of a group of colours that have the same blue-violet hue; a spectral colour
- (as adjective)
