used to describe a place that is very busy or crowded It's been like Piccadilly Circus in this house all morning. From the name of a busy area in the centre of London where several large roads meet and where there is always a lot of traffic. compare Grand Central Station Culture The streets that meet include Piccadilly, Regent Street and Shaftesbury Avenue. Many tourists go to Piccadilly Circus to see the statue of Eros and the brightly lit advertisements on the sides of the buildings. There is also a Piccadilly Circus station on the London Underground.