If the city of London is not London then where is London?

The City of London is the name of an area of London, where the stock markets are etc. London is a city, but the actual "City of London" is an area between East and Central London.

The City of London is only one square mile that formed the original city in Roman times. Now the City boundaries are from Aldgate in the east, Temple in the west, Bishopsgate in the north and London Bridge in the south.

The City of London is bordered by two further cities - the City of Westminster and the City of Southwalk (pronounced Suvuck by locals) which is in the south. All 3 of these cities are usually bunched together (along with the outer boroughs) as London. The definition of a city is a place which has a cathedral in it's boundaries. All 3 cities above do (St Paul's in the City, Westminster and Southwalk Cathedrals).

London city is a very small part of what we now call Greater London.