Here is the meaning of the word, OPERA

Opera ( 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.
Opera ( n. ) - The house where operas are exhibited.
Opera ( n. ) - The score of a musical drama, either written or in print; a play set to music.
Opera ( pl. ) - of Opus