/ Dictionary / Index M monomethylamine: Meaning and Definition of Find definitions for: mon•o•meth•yl•a•mine Pronunciation: (mon"u-meth'ul-u-mēn", -me-thil'u-min), [key] — n. Chem. methylamine. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. monometer monomial 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