INDIGO

noun (plural -gos or -goes) Etymology: Italian dialect, from Latin indicum, from Greek indikon, from neuter of indikos Indic, from Indos India Date: 1555 1. a blue vat dye obtained from plants (as ~ plants), the principal coloring matter C 16 H 10 N 2 O 2 of natural ~ usually synthesized as a blue powder with a coppery luster, ~ plant , a deep reddish blue