A condominium, or condo, is a form of housing tenure where a specified part of a piece of real estate (usually of an apartment house) is individually owned while use of and access to common facilities in the piece such as hallways, heating system, elevators, exterior areas is executed under legal rights associated with the individual ownership and controlled by the association of owners that jointly represent ownership of the whole piece. Colloquially, the term is often used to refer to the unit itself in place of the word "apartment".