A man owns a farm in fee simple. He deeds the farm to a friend until the friend dies, at which time a woman will acquire a fee simple title to the farm. The woman's interest in the farm is a:

remainder estate

Explanation: remainder estate in real property law simply refers to the interest in real property that is left after another interest in the property elapse, such as full title after a life estate. However a remainder must be created by a deed or will. And a life estate is a type of property ownership, typically established by a deed, which is often used to avoid probate and immediately transfer property to an heir, or remainderman, at the time of death.