Today, "London" usually refers to the region of London and the county-level administrative area of Greater London, which cover an identical area and are sub-divided into the thirty-two London Boroughs and the much smaller ancient City of London, often called 'The Square Mile'.
Historically, "London" referred to the City of London at the conurbation's heart, from which the city grew. Between 1889 and 1965 it referred to the former County of London which covered the area now known as Inner London. The metropolitan area of the County of London was previously covered by the Metropolitan Board of Works.
There are other definitions of "London" which cover varying areas, such as the Greater London Urban Area, the London postal districts; the area covered by the telephone area code 020; the area accessible by public transport using a Transport for London travelcard; the area delimited by the M25 orbital motorway; the Metropolitan Police District; and the London commuter belt.
