cou·pon n. A negotiable certificate attached to a bond that represents a sum of interest due. One of a set of detachable certificates that may be torn off and redeemed as needed: a food coupon. A detachable part, as of a ticket or advertisement, that entitles the bearer to certain benefits, such as a cash refund or gift. A certificate accompanying a product that may be redeemed for a cash discount. A printed form, as in an advertisement, to be used as an order blank or for requesting information or obtaining a discount on merchandise. A detachable slip calling for periodic payments, as for merchandise bought on an installment plan.