obbligato
/ˌɒblɪˈgɑːtəʊ/( <美> 亦作obligato)
noun
(pl. obbligatos 或obbligati /-tiː/)［usu. with or as modifier］
- an instrumental part, typically distinctive in effect, which is integral to a piece of music and should not be omitted in performance助奏声部。
词源
Italian, literally 'obligatory', from Latin obligatus, past participle of obligare （see OBLIGE）.