D defs.my
Entry 1 sense Webster, 1913

Triphthong

· Triph·thong · IPA /ˈtɹɪfˌθɔŋ/
01 n. A combination of three vowel sounds in a single syllable, forming a simple or compound sound; also, a union of three vowel characters, repr…
  1. 1.
    A combination of three vowel sounds in a single syllable, forming a simple or compound sound; also, a union of three vowel characters, representing together a single sound; a trigraph; as, eye, -ieu in adieu, -eau in beau, are examples of triphthongs.(Orthoepy)