One of the dwelling units in a condominium WordNet 3.0 & Open English WordNet

A condominium is an ownership regime in which a building is divided into multiple units that are either each separately owned, or owned in common with exclusive rights of occupation by individual owners. Wikipedia

A form of housing where the residents are co-owners of a housing complex, usually an apartment block or a group of multi-familiy homes, where the co-ownership grants the right to inhabit one housing unit and the obligation to maintain that unit. Common facilities and outer maintenance is funded by a set monthly fee that is paid by all co-owners. OmegaWiki