shifting executory interest

Noun

 * 1)  A third party interest in an estate in land created by the conditions of a grant wherein the grantor gives the land to a second party, but with the occurrence of a condition divesting the second party of the land in favor of the third party.
 * Joe gives land "to Mike, but if Harry graduates from law school, to Harry". Harry has an shifting executory interest because his graduation from law school divests Mike of ownership.