1 a travelling show of performing animals, acrobats, clowns, etc.
2 colloq. a a scene of lively action; a disturbance. b a group of people in a common activity, esp. sport.
3 Brit. an open space in a town, where several streets converge (Piccadilly Circus).
4 a circular hollow surrounded by hills.
5 Rom. Antiq. a a rounded or oval arena with tiers of seats, for equestrian and other sports and games. b a performance given there (bread and circuses).
Etymology: L, = ring
Useful english dictionary. 2012.