1.A defeat; an overthrow. (Obs.) "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. 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.
