Chorus
Broadly speaking, a
chorus is any substantial group of performers in a
play, revue,
musical or
opera who act more or less as one. It can also mean a work, or section of a work, performed by a chorus. Today, it is most usually used as a synonym for
choir to mean a group of
singers who all sing together or a piece sung by such a group, but it can also mean a group of dancers, and in
Greek drama it meant a group of
actors.
In colloquial usage, chorus is used to mean the refrain of a song.