noun
Linguistic term for a word or utterance consisting of a single syllable.
日本語では一音節の単語は比較的少ない。
In Japanese, monosyllabic words are relatively few.
音節 means 'syllable' in general, while 一音節 specifically means 'one syllable' or 'monosyllable'.
Compound of 一 (いち, 'one') + 音節 (おんせつ, 'syllable').