Indigo1. (n.) A kind of deep blue, one of the seven prismatic colors.
2. (n.) A blue dyestuff obtained from several plants belonging to very different genera and orders; as, the woad, Isatis tinctoria, Indigofera tinctoria, I. Anil, Nereum tinctorium, etc. It is a dark blue earthy substance, tasteless and odorless, with a copper-violet luster when rubbed. Indigo does not exist in the plants as such, but is obtained by decomposition of the glycoside indican.
3. (a.) Having the color of, pertaining to, or derived from, indigo.
Thesaurus Entries
Alice blue, Amytal, Amytal pill, Brunswick blue, Caelus, Capri blue, Chinese blue, Copenhagen blue, Demerol, Dolophine, Dresden blue, Fescennine, French blue, Gobelin blue, H, Luminal, Luminal pill, M, Mickey Finn, Nembutal, Nembutal pill, Persian blue, Pompeian blue, Prussian blue, Rabelaisian, Saxe blue, Seconal, Seconal pill, Tuinal, Tuinal pill, Wedgwood blue, X, absolute, air, alcohol, amobarbital sodium, analgesic, aniline blue, anodyne, aquamarine, atrabiliar, atrabilious, azo blue, azulene, azure, azure-blue, azure-colored, azurean, azured, azureness, azureous, azurite blue, baby blue, bad, barb, barbiturate, barbiturate pill, bawdy, benzoazurine, beryl, beryl-blue, berylline, bice, black, black stuff, bleu celeste, blue angel, blue devil, blue heaven, blue sky, blue turquoise, blue velvet, blueness, blueprint, bluish, bluishness, brine, briny, broad, cadaverous, cadet blue, caelum, calamine blue, calmative, canopy, canopy of heaven, cerulean, ceruleous, cerulescent, chloral hydrate, ciba blue, coarse, cobalt, codeine, codeine cough syrup, cold-type proof, color proof, complete, computer proof, cope, cornflower, corpselike, crestfallen, cyan, cyanean, cyanine blue, cyanosis, dark-blue, deadly, deathlike, deathly, deathly pale, deep, deep-blue, dejected, delft blue, depressant, depressed, depressor, despondent, dirty, disconsolate, dismal, dispirited, dolly, down, downcast, downer, downhearted, downright, drink, eerie, empyrean, erotic, ether, filthy, firmament, foul, foul-mouthed, foul-spoken, foul-tongued, foundry proof, fulsome, funky, galley, galley proof, garter blue, ghastly, ghostlike, ghostly, glaucous blue, gloomy, glum, goofball, grisly, gruesome, haggard, hard stuff, heaven, heavens, heroin, hop, horse, hyacinth, hyaline, hypnotic, improper, impure, indecent, indelicate, indigo, indigo white, infernal, isamine blue, ithyphallic, jouvence blue, junk, knockout drops, lapis lazuli blue, laudanum, lavender blue, lewd, lift, lifts, light-blue, lightish-blue, liquor, livid, lividity, lividness, lotus, low, low-spirited, lurid, macabre, madder blue, main, marine blue, melancholic, melancholy, meperidine, methadone, methylene azure, methylene blue, morose, morphia, morphine, mortuary, narcotic, nasty, navy, navy blue, new blue, obscene, off color, off-color, offensive, old blue, opiate, opium, out-and-out, pacifier, page proof, pain killer, pale, paregoric, pavonian, pavonine, peacock blue, peacock-blue, pen yan, pensive, perfect, phenobarbital, phenobarbital sodium, plate proof, pompadour green, pornographic, positive, powder blue, press proof, progressive proof, proof, proof sheet, pull, purple, purple heart, quietener, racy, rainbow, raunchy, red, regular, repro proof