Pronunciation: (trif'thông, -thong, trip'-), [key]
1. Phonet.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.
2. (not in technical use) a trigraph.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.