executory interest

 

A future interest in property that will be triggered on the happening of a stated event.  For example, to A and his heirs, but if A dies without marrying, to B and his heirs.   B has an executory interest.

An executory interset can be springing (meaning the previous interest was held by the grantor) or shifting (meaning the previous interest was held by someone other then the grantor).

See:  Future Interest.