Piccadilly Circus is a road junction

Junction (road)

A road junction is a location where vehicular traffic going in different directions can proceed in a controlled manner designed to minimize accidents. In some cases, vehicles can change between different routes or directions of travel.-Origins:...

 and public space of London

London

London is the capital city of :England and the :United Kingdom, the largest metropolitan area in the United Kingdom, and the largest urban zone in the European Union by most measures. Located on the River Thames, London has been a major settlement for two millennia, its history going back to its...

's West End

West End of London

The West End of London is an area of central London, containing many of the city's major tourist attractions, shops, businesses, government buildings, and entertainment . Use of the term began in the early 19th century to describe fashionable areas to the west of Charing Cross...

 in the City of Westminster

City of Westminster

The City of Westminster is a London borough occupying much of the central area of London, England, including most of the West End. It is located to the west of and adjoining the ancient City of London, directly to the east of the Royal Borough of Kensington and Chelsea, and its southern boundary...

, built in 1819 to connect Regent Street

Regent Street

Regent Street is one of the major shopping streets in London's West End, well known to tourists and Londoners alike, and famous for its Christmas illuminations...

 with the major shopping street of Piccadilly

Piccadilly

Piccadilly is a major street in central London, running from Hyde Park Corner in the west to Piccadilly Circus in the east. It is completely within the city of Westminster. The street is part of the A4 road, London's second most important western artery. St...

. In this context, a circus, from the Latin word meaning "circle", is a round open space at a street junction.
Piccadilly now links directly to the theatres on Shaftesbury Avenue

Shaftesbury Avenue

Shaftesbury Avenue is a major street in central London, England, named after Anthony Ashley Cooper, 7th Earl of Shaftesbury, that runs in a north-easterly direction from Piccadilly Circus to New Oxford Street, crossing Charing Cross Road at Cambridge Circus....

, as well as the Haymarket

The Haymarket

Haymarket is a street in the St. James's district of the City of Westminster, London. It runs from Piccadilly Circus at the north to Pall Mall at the south...

, Coventry Street

Coventry Street

Coventry Street is a short London street, within the City of Westminster, running from Piccadilly Circus to Leicester Square. The street is the main conduit between Piccadilly Circus and Leicester Square and at the weekend up to 150,000 people walk from one to another along the street...

 (onwards to Leicester Square

Leicester Square

Leicester Square is a pedestrianised square in the West End of London, England. The Square lies within an area bound by Lisle Street, to the north; Charing Cross Road, to the east; Orange Street, to the south; and Whitcomb Street, to the west...

), and Glasshouse Street. The Circus is close to major shopping and entertainment areas in the West End.