Activity centre is a term used in urban planning and design for a mixed-use urban area where there is a concentration of commercial and other land uses. For example, the central business districts of cities (CBD) are also known as “Central Activities Districts” (CAD) (also known as Downtown in North America or "Central Activities Zone" in the United Kingdom) in recognition of the fact that it is right that commercial functions are not the only things that occur there. The term activity centre can also be used to designate an area for mixed-use development, whatever its current land use happens to be.