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, triphthong单元音 词源early 17th cent.: from Greek monophthongos, from monos ‘single’ + phthongos ‘sound’.