In theatre, a group of actors, singers, or dancers who perform as an ensemble to describe and comment on a play's action.
Choral performances, which originated in the singing of dithyramb s in honour of Dionysus , dominated Greek drama until the mid-5th century BC, when Aeschylus added a second actor and reduced the chorus from 50 to 12 performers. As the importance of individual actors increased, the chorus gradually disappeared. It was revived in modern plays such as Eugene O'Neill 's Mourning Becomes Electra (1931) and T.S. Eliot 's Murder in the Cathedral (1935). Choruses of singers and dancers came to be featured in musical comedies, especially in the 20th century, first as entertainment and later to help develop the plot.