The latter includes the Greater Toronto Area's satellite municipalities, such as Peterborough, Barrie, Guelph, Kitchener, Waterloo, Cambridge and the Niagara Region. In 2006, the term began to be supplanted in the field of spatial planning as provincial policy increasingly began to refer to either the " Greater Toronto and Hamilton Area" (GTHA) or the still-broader " Greater Golden Horseshoe".
However, it did not come into everyday usage until the mid- to late 1990s. The use of the term involving the four regional municipalities came into formal use in the mid-1980s, after it was used in a widely discussed report on municipal governance restructuring in the region and was later made official as a provincial planning area. The term "Greater Toronto" was first used in writing as early as the 1900s, although at the time, the term only referred to the old city of Toronto and its immediate townships and villages, which became Metropolitan Toronto in 1954 and became the current city of Toronto in 1998.