triphthong

noun

triph·​thong ˈtrif-ˌthȯŋ 

ˈtrip-

1

: a phonological unit consisting of three successive vocalic sounds in one syllable

2

: trigraph

triphthongal

trif-ˈthȯŋ-gəl 

trip-

-əl

adjective

Word History

Etymology

tri- + -phthong (as in diphthong)

First Known Use

circa 1599, in the meaning defined at sense 1