All 5 Uses of

opera
in
My Antonia

On Saturday nights, Mrs. Harling used to play the old operas for us—'Martha,' 'Norma,' 'Rigoletto'—telling us the story while she played.†
Book 2 *

operas = classical music plays in which most of the dialogue is sung

He gave a concert at the Opera House on Monday night, and he and his manager spent Saturday and Sunday at our comfortable hotel.†
Book 2

Mrs. Harling came to the Opera House to hear the Commencement exercises, and I looked at her most of the time while I made my speech.†
Book 2

There was a note on the programme, saying that the 'incidental music' would be from the opera 'Traviata,' which was made from the same story as the play.†
Book 3

Definitions:

(1) (opera)
a musical play with orchestra in which most dialogue is sung -- (typically associated with classical music and often in a language foreign to the audience)

or:

the art form (or describing something as related to it) that consists of musical plays with orchestra in which most dialogue is sung
(2) (meaning too rare to warrant focus)
meaning too rare to warrant focus:

Less commonly, the expression, soap opera, refers to a television or radio program that typically runs for many years and dramatizes the lives of a group of characters.