Defeasance
Defeasance , noun
[Old French defesance, from defesant, French défaisant, present participle of defaire, French défaire, to undo. See Defeat.]
1.
A defeat; an overthrow. [Obsolete]
After his foes' defeasance.
2.
A rendering null or void.
3.
(Law) A condition, relating to a deed, which being performed, the deed is defeated or rendered void; or a collateral deed, made at the same time with a feoffment, or other conveyance, containing conditions, on the performance of which the estate then created may be defeated.
Mortgages were usually made in this manner in former times, but the modern practice is to include the conveyance and the defeasance in the same deed.