monophthong
noun /ˈmɒnəfθɒŋ/, /ˈmɒnəθɒŋ/
/ˈmɑːnəfθɔːŋ/, /ˈmɑːnəθɔːŋ/
(phonetics)- a speech sound that consists of only one vowel sound, for example the /uː/ sound in queue /kjuː/ compare diphthong, triphthongWord Originearly 17th cent.: from Greek monophthongos, from monos ‘single’ + phthongos ‘sound’.