/ Dictionary / Index I indigo blue: Meaning and Definition of Find definitions for: in'digo blue' Pronunciation: [key] indigo (def. 4). a dark-blue, water-insoluble, crystalline powder, CHNO, having a bronzelike luster, the essential coloring principle of which is contained along with other substances in the dye indigo and which can be produced synthetically. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. indigo indigo bunting Related Content Daily Word Quiz: acquiesce Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language