Tenancy in Common
Tenancy in common is a type of shared ownership of property, where each owner owns a share of the property. Unlike in a joint tenancy, these shares can be of unequal size, and can be freely transfered to other owners both during life and via a will. Even if owners own unequal shares, however, all owners have the right to occupy and use all of the property. If A and B own a house as tenants in common, there is no problem if A owns 1/3 of the house and B owns 2/3, and no problem if A decides to sell his share to C.
www.law.cornell.edu/wex/tenancy_in_common