All 4 Uses

opera
in
Flora & Ulysses
(Edited)

...someone was singing. It was opera.
p. 115.2 *

opera = a song from a classical music play in which most of the dialogue is sung
Opera music.
p. 115.2

opera = a musical play with orchestra in which most of the dialogue is sung (or the art form that consists of such musicals; or describing something as related to that art form)
The opera music was very loud now Flora looked down at the hand that was on her arm.
p. 116.2
The opera music ended.
p. 123.8

Definitions:

(1) (opera)
a form of musical theater with orchestra in which most of the words are sung, often in a classical style and sometimes in a foreign language
(2) (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.