in the united states, some apartment-dwellers own their units, either as a housing cooperative, in which the residents own shares of a corporation that owns the building or development; or in a condominium, whose residents own their apartments and share ownership of the public spaces. most apartments are in buildings designed for the purpose, but large older houses are sometimes divided into apartments. the word "apartment" denotes a residential unit or section in a building. in some locations, particularly the united states, the word connotes a rental unit owned by the building owner, and is not typically used for a condominium.