/ Dictionary / Index T trisubstituted: Meaning and Definition of Find definitions for: tri•sub•sti•tut•ed Pronunciation: (trī-sub'sti-t"tid, -ty"-), [key] — adj. Chem. pertaining to a molecule containing three substituents. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. tristylous trisulfide Related Content Daily Word Quiz: agitated Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language