Final answer:
The legal term describing when a creditor accepts a lesser amount as full payment is 'accord and satisfaction'.
Step-by-step explanation:
The legal term that refers to the situation when a creditor agrees to accept as payment in full what the payer reimburses is accord and satisfaction. This is a common method used in dispute resolution where the creditor agrees to discharge a debt in exchange for a payment of less than what is owed, often due to the debtor's inability to pay the full amount. This agreement must be voluntary, and both parties must consent to the new terms of settlement.