The term 'cash back' refers to a type of financial transaction in which a customer receives a REFUND or REBATE for a purchase they have made. The crossword solutions for this term are 'REFUND' (6 letters), 'REBATE' (6 letters), and 'IER' (3 letters). REFUND and REBATE are both terms used to describe the return of money to a customer after a purchase, while IER stands for 'instant electronic REBATE, ' which is a type of REBATE that is applied directly to a customer's credit card or bank account.