/ Dictionary / Index T trigraph: Meaning and Definition of Find definitions for: tri•graph Pronunciation: (trī'graf, -gräf), [key] — n. a group of three letters representing a single speech sound, as eau in beau. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. trigram trihedral Related Content Daily Word Quiz: gregarious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language