/ Dictionary / Index T triphthong: Meaning and Definition of Find definitions for: triph•thong Pronunciation: (trif'thông, -thong, trip'-), [key] — n. a monosyllabic speech-sound sequence perceived as being made up of three differing vowel qualities, as the pronunciation of our, esp. in r-dropping dialects. (not in technical use) a trigraph. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. triphosphoric acid triphylite Related Content Daily Word Quiz: cygnet Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language