Mich. Comp. Laws § 554.61: Terminable interest, specified contingency; definitions.

Sec. 1.

As used in this act:

"Terminable interest" is a possessory or ownership interest in real property which is subject to termination by a provision in a conveyance or other instrument which either creates a right of reversion to a grantor or his heirs, successors or assigns or creates a right of entry on the occurrence of a specified contingency.

"Specified contingency" is the event described in a conveyance or other instrument creating a terminable interest, the occurrence of which requires or permits the divesting of the terminable interest.