noun
treble; high singing voice
Refers to the high-pitched part in music, especially vocal music. Often used in choral or instrumental contexts.
合唱で高音部を担当しています。
I am in charge of the treble part in the choir.
この曲の高音部はとても難しい。
The high part of this piece is very difficult.
ソプラノ is a specific voice type (soprano), while 高音部 is a more general term for any high-pitched part.
Compound of 高音 (こうおん, 'high-pitched sound') and 部 (ぶ, 'section, part').