The term inner city has been used, especially in the US, as a euphemism for lower-income residential districts in the downtown or city centre. Sociologists sometimes turn this euphemism into a formal designation, applying the term "inner city" to such residential areas, rather than to geographically more central commercial districts.
The word downtown is also used to describe the inner city or city centre–primarily in North America–by English language to refer to a city's commercial, cultural and often the historical, political and geographic heart, and is often contiguous with its central business district. In British English, the term "city centre" is most often used, " centre-ville" in French, Stadtzentrum in German, or shìzhōngxīn (市中心) in Chinese). The two terms are used interchangeably in Canada. A few US cities, such as Philadelphia, use the term "Center City".
/ref> Also, some inner-city areas in various places have undergone the socioeconomic process of gentrification, especially since the 1990s. (Brookings Institution) and its analysis in — see example in