The term circus has a number of meanings.
In the modern world, a circus is a traveling entertainment show, generally presented in a large tent or 'big top', with displays by clowns, acrobats, trapeze artists, etc, and often (though less frequently than in former years) performing animals such as horses, elephants, lions and tigers. Arising from this usage, political conferences and similar events are often satirically described as 'circuses'.
The meeting point of a number of roads, at a circular plaza, is often also described as a circus. Famous London circuses include Piccadilly Circus, Oxford Circus, Cambridge Circus, Finsbury Circus, Holborn Circus and St George's Circus.