A performer who does not appear every night but knows several ensemble parts and can fill any of them.
Swings are the quiet heroes of big musicals. A single swing may know eight or ten different ensemble tracks: every step, every harmony, every costume change and every prop for each one. When someone in the ensemble is out, or moves up to cover a lead, a swing slips into their place, sometimes with only an hour's notice.
Also seen as: swing performer, universal swing, swing track