A term of contract law by which one party, having complied with its obligation under a contract, accepts some type of compensation from the other party (usually money and of a lesser value) in lieu of enforcing the contract and holding the other party to their obligation.
This discharges the contract.
The definition cited by lawyers is usually that found in British Russian Gazette & Trade Outlook Ltd. v. Associated Newspapers Ltd. (1933) 2 K.B. 616:
"Accord and satisfaction is the purchase of a release from an obligation arising under contract or tort by means of any valuable consideration, not being the actual performance of the obligation itself. The accord is the agreement by which the obligation is discharged. The satisfaction is the consideration which makes the agreement operative."