複ふく合ごう母ぼ音いん

Meanings

1

noun

compound vowel; complex vowel

linguistics

Linguistics term for a vowel sound that combines two or more vowel qualities, such as a diphthong or triphthong.

sound, noise

二に重じゅう母ぼ音いん
二重母音 specifically refers to a diphthong (two vowel qualities), while 複合母音 is a broader term that can include triphthongs or other complex vowel combinations.
単たん母ぼ音いん
単母音 is a simple or pure vowel with a single, steady quality, contrasting with the combined qualities of a 複合母音.

Compound of 複合 (fukugō, 'compound') and 母音 (boin, 'vowel'). The term is a direct calque from Western linguistic terminology.