\Meth"yl*ene\, n. [F. m['e]thyl[`e]ne, from Gr. ? wine
+ ? wood; -- a word coined to correspond to the name wood
spirit.] (Chem.)
A 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}.

{Methylene blue} (Chem.), an artificial dyestuff consisting
   of a complex sulphur derivative of diphenyl amine; --
   called also {pure blue}.