/ Dictionary / Index T trifunctional: Meaning and Definition of Find definitions for: tri•func•tion•al Pronunciation: (trī-fungk'shu-nl), [key] — adj. Chem. pertaining to molecules that can react at three sites. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. triform trifurcate Related Content Daily Word Quiz: censure Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language