A payment refund is the return of money from a merchant or other payee to the customer after a payment has been completed, and the topic is covered in full under refund. The longer phrase is used mainly in payments documentation and provider dashboards, where it helps distinguish a refund of a payment from other kinds of refund, such as tax refunds.
In card payments, a refund is a separate credit transaction that the merchant sends through its acquirer, usually linked to the original purchase. It differs from a void, which cancels a transaction before it settles, and from a chargeback, which the cardholder's issuer raises when the cardholder disputes a charge. For bank transfers and account-to-account payments, a refund is normally a new outbound transfer from the payee back to the payer, since the original payment cannot be pulled back.
Refunds can be full or partial, as described under partial refund. Their handling, including timing, fees and records, is covered under refund processing, and merchants should watch for refund fraud.