/ Dictionary / Index M monosubstituted: Meaning and Definition of Find definitions for: mon•o•sub•sti•tut•ed Pronunciation: (mon"u-sub'sti-t"tid, -ty"-), [key] — adj. Chem. containing one substituent. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. monostylous monosyllabic Related Content Daily Word Quiz: abominable Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language