of or relating to that group of vat dyes that have a molecular structure similar to that of indigo.
an indigoid substance.
Origin of indigoid
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
of, concerned with, or resembling indigo or its blue colour
any of a number of synthetic dyes or pigments related in chemical structure to indigo
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012