A payment offered in full settlement by the debtor and accepted by a creditor is known as:

Accord and satisfaction is a legal contract where a debtor offers, and a creditor accepts, a different performance (often a lesser payment) to satisfy an existing, disputed debt. The "accord" is the agreement to settle, and the "satisfaction" is the execution of that agreement. A liquidated debt is one where the amount is certain and undisputed, which typically cannot be settled for less without additional consideration.