An apartment or a flat is a self-contained housing unit that occupies only part of a building. Such a building may be called an apartment building, apartment house , block of flats, tower block, high-rise or, occasionally mansion block , especially if it consists of many apartments for rent. In Scotland it is often called a tenement, which has a pejorative connotation elsewhere. Apartments may be owned by an owner/occupier by leasehold tenure or rented by tenants .
The term apartment is favored in North America (although flat is used in the case of a unit which is part of a house containing two or three units, typically one to a floor) and also is the preferred term in Ireland. The term flat is commonly, but not exclusively, used in the United Kingdom, Singapore, Hong Kong and most Commonwealth nations.
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. This usage has also been appearing in British English where apartment is used to denote expensive 'flats' in exclusive and expensive residential areas in, for example, parts of London such as Belgravia and Hampstead.