noun
solmization
Technical term in music education and theory for the system of assigning syllables (do, re, mi, etc.) to musical notes.
音楽の授業で階名唱法を使って歌を練習した。
We practiced the song using solmization in music class.
ソルフェージュ is a broader term for ear training and sight-singing, while 階名唱法 specifically refers to the solmization system within that training.
Compound of 階名 (syllable names of the scale) and 唱法 (method of singing). The exact historical derivation is uncertain; the term is a modern technical coinage for solmization.