— triphthongal /trif thawng"geuhl, -thong"-, trip-/ , adj.
/trif"thawng, -thong, trip"-/ , n.
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.
[ 1590-1600; triphthongus tríphthongos with three vowels, equiv. to tri- TRI- + phthóngos voice, sound ]