1. a speech sound that consists of only one vowel sound, for example the /uː/ sound in queue /kjuː/ Compare : diphthong, triphthong
   Word Originearly 17th cent.: from Greek monophthongos, from monos ‘single’ + phthongos ‘sound’.

   Definitions on the go

   Look up any word in the dictionary offline, anytime, anywhere with the Oxford Advanced Learner’s Dictionary app.

[TahlilGaran] English Dictionary ▲