A suburb (or suburban area or suburbia) is a mixed-use or residential area, existing either as part of a city/urban area, or as a separate residential community within commuting distance of one. Suburbs might have their own political or legal jurisdiction, especially in the United States, but this is not always the case, especially in the United Kingdom where most suburbs are located within the administrative boundaries of cities. In most English-speaking countries, suburban areas are defined in contrast to central or inner city areas, but in Australian English and South African English, suburb has become largely synonymous with what is called a "neighborhood" in other countries, and the term encompasses inner city areas.