noun which may take the genitive case particle 'no', noun
unrounded
Technical term in phonetics describing vowels produced without lip rounding. Used attributively with の, as in 非円唇母音 (unrounded vowel).
The Japanese 'i' is an unrounded vowel.
Compound of 非 (hi, 'non-') and 円唇 (enshin, 'rounded lips'), a calque from Western linguistic terminology.