What is a fee simple estate that returns to the original grantor when a specific condition occurs called?

A fee simple estate that returns to the original grantor when a specific condition occurs is referred to as a determinable fee estate. This type of estate is characterized by a condition that, if violated, results in the automatic reversion of the property back to the grantor. The distinguishing feature of a determinable fee estate is that the grantor has included a specific condition or limitation in the grant of the property.

For example, if a property is conveyed with the stipulation that it can only be used for educational purposes, if that condition is not met, the property automatically reverts to the original owner. This automatic return is a critical characteristic of a determinable fee estate.

In contrast, a life estate is granted for the duration of an individual's life and doesn't revert to the original grantor upon a condition, but rather at the death of the life tenant. A fee simple absolute is the most complete ownership interest one can have, with no specific conditions or limitations attached. A conditional fee estate, while it may seem similar to a determinable fee estate, typically involves conditions that require action or inaction, rather than automatic reversion upon the occurrence of a specific condition.