a travelling company of acrobats, clowns, and other entertainers which gives performances, typically in a large tent, in a series of different places

I was thrilled by the annual visits of the circus

a circus elephant

(in ancient Rome) a rounded or oval arena lined with tiers of seats, used for equestrian and other sports and games

the Circus Maximus

a rounded open space in a town or city where several streets converge

Piccadilly Circus