(n.) A drama, either tragic or comic, of which music forms an
essential part; a drama wholly or mostly sung, consisting of
recitative, arials, choruses, duets, trios, etc., with orchestral
accompaniment, preludes, and interludes, together with appropriate
costumes, scenery, and action; a lyric drama.
(n.) The score of a musical drama, either written or in print; a
play set to music.
(n.) The house where operas are exhibited.
(pl. ) of Opus