A theatrical work, combining drama, music, song and sometimes dance.
The score for such a work.
A building designed for the performance of such works; an opera house.
A company dedicated to performing such works.
(by extension) Any showy, melodramatic or unrealistic production resembling an opera.
A work of music or set of works with a specified rank in an ordering of a composer's complete published works.
A work, especially of art.