(Ancient Greece, historical) A group of singers and dancers in a theatrical performance or religious festival who commented on the main performance in speech or song.

(Ancient Greece, historical) A song performed by the singers of such a group.

(Ancient Greece, historical) A group of singers and dancers who comment on the main performance and perform songs.

(by extension, chiefly Britain, theater, historical) An actor who reads the prologue and epilogue of a play, and sometimes also acts as a commentator or narrator; also, a portion of a play read by this actor.

A group of singers performing together; a choir; specifically, such a group singing together in a musical, an opera, etc., as distinct from the soloists; an ensemble.

(by extension) A group of people in a performance who recite together.

An instance of singing by a group of people.

(figurative) A noun "chorus" represents a group of people, animals, or inanimate objects who make sounds together or the noise made by such a group.

(figurative) A noun "chorus" represents a group of people expressing a unanimous opinion or the opinion expressed by such a group.

(music) A musical piece sung by a choir, a repeated part of a song, the main part of a pop song, a group of organ pipes, a feature in electronic music, a simple song for informal worship, and the improvised solo section in jazz.

(transitive) Sing, express, or recite in unison; agree or echo with someone else's statement; provide a song with a chorus or refrain.

(intransitive) Sing the chorus or refrain of a song, sing or say in unison, echo another person's words in unison, or make cries or sounds together (for animals).