Wikipedia
A chorus (, khoros), in the context of Ancient Greek tragedy, comedy, and satyr plays, is a homogeneous, non-individualised group of performers, who comment with a collective voice on the dramatic action. The chorus consisted of between 12 and 50 players, who variously danced, sang or spoke their lines in unison and sometimes wore masks.
Usage examples of "greek chorus".
But we'll do without the Ancient Greek Chorus bit, if you don't mind.
The rest of us served as Greek chorus to the grand single Aeschylean protagonist.
Like the Greek chorus he comments on the action and fills you in on the background, but he has greater power than that.
Angela asked them, and they told the story in a kind of Greek chorus, interrupting each other frequently: a single explosion had burst the dome like a balloon, causing an instantaneous decompression that had also blown up many of the town's buildings.