/ Dictionary / Index M methylation: Meaning and Definition of Find definitions for: meth•yl•a•tion Pronunciation: (meth"u-lā'shun), [key] — n. Chem. the process of replacing a hydrogen atom with a methyl group. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. methylated spirits methylbenzene Related Content Daily Word Quiz: dissonant Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language