/ Dictionary / Index M methyl transferase: Meaning and Definition of Find definitions for: meth'yl trans'ferase Pronunciation: [key] any of a class of enzymes that catalyze the transfer of methyl groups from one molecule to another. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. methylthionine chloride methyltrinitrobenzene Related Content Daily Word Quiz: perspicacious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language