Downtown is a term primarily used in North America to refer to a city's sometimes commercial, cultural and often the historical, political, and geographic heart. It is often synonymous with its central business district (CBD). It may also be a center for shopping and entertainment. Downtowns typically contain a small percentage of a city's employment but are concentrated in services, including high-end services (office or white-collar jobs).[1][2] Sometimes, smaller downtowns include lower population densities and nearby lower incomes than suburbs.[3][4] It is often distinguished as a hub of public transit and culture.[5]