New York Laws
Part 4 - Estates Defined
6-4.9 - Definition of a Future Estate Vested Subject to Complete Defeasance


defeasance

A future estate vested subject to complete defeasance is an estate
created in favor of one or more ascertained persons in being, which
would become an estate in possession upon the expiration of the
preceding estates, but may end or may be terminated as provided by the
creator at, before or after the expiration of such preceding estates.