methylene blue met·hy·le·neblue uncommon noun 1. a dark green dye used as a stain, an antiseptic, a chemical indicator, and an antidote in cyanide poisoning Synonymsmethylene bluemethylthionine chloride Related words Broader terms stainthiazine WordNet 2.1 (Princeton University). WordNet 2.1 Copyright Princeton University. All rights reserved.
