A central business district (CBD) is the commercial and business center of a city. It contains commercial space and offices, and in larger cities will often be described as a financial district. Geographically, it often coincides with the "city center" or "downtown". However, these concepts are not necessarily synonymous: many cities have a central business district located away from its commercial and/or cultural center and/or downtown/city center, and there may be multiple CBDs within a single urban area. The CBD will often be highly accessible and have a large variety and concentration of specialized goods and services compared to other parts of the city.

A city centre is the commercial, cultural and often the historical, political, and geographic heart of a city. The term "city centre" is primarily used in British English, and closely equivalent terms that exist in other languages, such as "centre-ville" in French, Stadtzentrum in German, or shìzhōngxīn (市中心) in Chinese. In the United States, the term "downtown" is generally used, though a few cities, like Philadelphia, use the term "Center City" or "City Center".