Breadcrumb Home > Dictionary > Index M methylene: Meaning and Definition of Find definitions for: meth•yl•ene Pronunciation: (meth'u-lēn"), [key] — adj. Chem. containing the methylene group. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: methylene (Thesaurus) methyldopa methylene blue ✖ Related Content Daily Word Quiz: sophism Analogy of the Day: Today’s Analogy Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language