What is Rescission?

Legal Definition
In contract law, rescission has been defined as the unmaking of a contract between parties. Rescission is the unwinding of a transaction. This is done to bring the parties, as far as possible, back to the position in which they were before they entered into a contract (the status quo ante).
-- Wikipedia
Legal Definition
Cancellation of a contract. Rescission may be unilateral, as when a party rightfully cancels a contract because of another party's material breach. Rescission can also be mutual, as when the contracting parties agree to discharge all remaining obligations. Finally, courts can use rescission as a synonym for voiding a contract, as for reasons of public policy.
Legal Definition
Rescission or the act of rescinding, is where a contract is canceled, annulled or abrogated by the parties or one of them. In Spanish law, nullity is divided into absolute and relativeThe former is that which arises from a law, whether civil or criminal, the principal motive for which is the public interest ; and the latter is that which affects only certain individuals. "Nullity" is not to be confounded with "rescission." Nullity takes place when the act is affected by a radical vice, which prevents it from producing any effect; as where an act is in contravention of the laws or of good morals, or where it has been executed by a person who cannot be supposed to have any will, as a child under the age of seven years, or a. madman, (uno o demente.) Rescission is where an act, valid in appearance, nevertheless conceals a defect, which may make it null, if demanded by any of the parties; as, for example, mistake, force, fraud, deceit, want of sufficient age, etc. Nullity relates generally to public order, and cannot therefore be made good either by ratification or prescription; so that the tribunals ought, for this reason alone, to decide that the null act can have no effect, without stopping to inquire whether the parties to it have or have not received any injury. Rescission. on the contrary, may be made good by ratification or by the silence of the parties; and neither of the parties can demand it, unless he can prove that he has received some prejudice or sustained some damage by the act. Sunol v. Hepburn, 1 Cal. 281, citing Escriche.
-- Black's Law Dictionary
Legal Definition
The cancellation, avoid. ance, unmaking or termination of contract. See 153 U. S. 540, 38 L. Ed. 814, 14 Sup. Ct. Rep. 876. An equitable remedy to have a contract canceled.
-- Ballentine's Law Dictionary