chorus

In classical Greek drama, the group of actors who jointly comment on the main action or advise the main characters. The action in Greek plays took place offstage; the chorus provided a link in the drama when the principals were offstage. The chorus did not always speak in unison; it was common for members of the chorus to show some individuality. The device of a chorus has also been used by later dramatists.

chorus

In opera or oratorio, a large group of singers providing an accompaniment in four or more parts to principal soloists. The term also describes a body of usually untrained male and female singers of secular unison songs, or providing the refrain element of solo verse songs.