noun A theatrical work, combining drama, music, song and sometimes dance; usually, one sung-through, based on classical music and seen as more artistic and formalized than other forms of musical theater.
noun The score for such a work.
noun The genre of such works, the art of composing operas.
noun A building designed for the performance of such works; an opera house.
noun A company dedicated to performing such works.
noun Any showy, melodramatic or unrealistic production resembling an opera.