noun
operetta
A light opera, typically shorter and with spoken dialogue. Used in musical contexts.
from Italian
来月、劇場でオペレッタを上演する。
They will perform an operetta at the theater next month.
オペラ (opera) is a full-scale dramatic work, while オペレッタ (operetta) is lighter and often includes spoken dialogue.
Borrowed from Italian 'operetta', a diminutive of 'opera'.