con·do·min·i·um / ˌkändəˈminēəm/ • n. (pl. -ums) 1. a building or complex of buildings containing a number of individually owned apartments or houses. ∎ each of the individual apartments or houses in such a building or complex. ∎ the system of ownership by which these operate, in which owners have full title to the individual apartment or house and an undivided interest in the shared parts of the property.2. the joint control of a country's or territory's affairs by other countries. ∎ a state so governed.