Methylene blue Meaning, Definition & Usage

  1. noun a dark green dye used as a stain, an antiseptic, a chemical indicator, and an antidote in cyanide poisoning
    methylthionine chloride.

WordNet

Definitions
  1. (Chem.), an artificial dyestuff consisting of a complex sulphur derivative of diphenyl amine; called also pure blue.

Webster 1913