What is the term for an estate where the holder has a fee simple title that may be divested upon the occurrence of a specified event?

The term for an estate where the holder has a fee simple title that may be divested upon the occurrence of a specified event is known as a defeasible fee estate. This type of estate is characterized by its conditional nature, meaning that the ownership can be lost or "defeated" if a particular event occurs or a condition is not met. This event can typically be a breach of a certain stipulation that was agreed upon when the property was transferred.

In contrast, a fee simple absolute represents the most complete form of ownership, which is not subject to any conditions or limitations, and thus does not have the possibility of being divested based on specific events. A life estate grants ownership of the property only for the duration of the life of a specified individual, after which the property reverts to the original grantor or goes to another party and does not involve conditional limitations. Lastly, a leasehold estate entails an agreement where one party (the tenant) has the right to use and occupy the property of another (the landlord) for a specific term, often with defined conditions, but it does not involve fee simple title, making it distinct from a defeasible fee estate.