1. A defeat; an overthrow. [Obs.]
After his foes' defeasance. --Spenser.
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.
Note: ☞ 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.