1. (n.) An herbaceous cruciferous plant (Isatis tinctoria). It was formerly cultivated for the blue coloring matter derived from its leaves.

2. (n.) A blue dyestuff, or coloring matter, consisting of the powdered and fermented leaves of the Isatis tinctoria. It is now superseded by indigo, but is somewhat used with indigo as a ferment in dyeing.

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