Ownership of the same property, jointly and concurrently, by several persons each of whom is privately vested with a share of the right of ownership.

Co-ownership is called undivided when the right of ownership is not accompanied by a physical division of the property (e.g. co-operative housing).
It is called divided when the right of ownership is apportioned among the co-owners in fractions, each comprising a physically divided private portion and a share of the common portions.

(Ref.: Art. 1010 C.C.Q.)