An apartment (in US English) or flat (in British English) is a self-contained housing unit (a type of residential real estate) that occupies only part of a building. Such a building may be called an apartment building, especially if it consists of many apartments for rent. Apartments may be owned by an owner/occupier or rented by tenants (two types of housing tenure).
The term apartment is favored in North America, whereas the term flat is commonly, but not exclusively, used in the United Kingdom, Hong Kong and most Commonwealth countries. In Malaysian English, flat often denotes a housing block of lesser quality meant for lower-income groups, while apartment is more generic and may also include luxury condominiums.
Tenement law refers to the feudal basis of permanent property such as land or rents. May be found combined as in "Messuage or Tenement" to encompass all the land, buildings and other assets of a property.