Methylene (?), n. [F. méthylène, from Gr. &unr_; wine + &unr_; wood; -- a word coined to correspond to the name wood spirit.] (Chem.) A divalent hydrocarbon radical, -CH2-, not known in the free state, but regarded as an essential residue and component of certain derivatives of methane; as, methylene bromide, CH2Br2; -- formerly called also methene.
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Methylene blue (Chem.), an artificial dyestuff consisting of a complex sulphur derivative of diphenyl amine; -- called also pure blue.
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