similar purpose but different underlying security
There are multiple definitions - click on the translation that matches your context.
a ticket or document that can be redeemed (=exchanged) for a discount (=price reduction) when buying a product
Our supermarket would never use loyalty cards to promote tobacco or baby milk, but we are planning to send out wine coupons.
the interest rate on a fixed income security (eg a bond); the term for each interest payment made to the bondholder
A $500 bond with a 4% coupon pays $20 a year. Two payments of $10 each would be made.