Joint Tenancy

 A type of shared ownership of property, where each owner has an undivided interest in the property.  This type of ownership creates a right of survivorship, which means that when one owner dies, the other owners absorb the deceased owner's interest.  For example, if A and B own a house as joint tenants, both have undivided ownership of the property, and the full right to occupy and use all of it.  If A dies, B gets sole ownership of the house, because of the right of survivorship.  

Joint tenancies are generally disfavored by courts, who would prefer to find a property is owned via a tenancy in common.