DEFINITION of 'International Reply Coupon - IRC'
A coupon that can be exchanged for the adequate minimum postage required for unregistered priority airmail weighing up to 20 grams. Mail items utilizing IRCs must be sent only to another Universal Postal Union (UPU) member country. Although UPU member postal services are not required to sell IRCs, they are obligated to exchange them for postage. It is basically a coupon that can be exchanged for postage stamps.
BREAKING DOWN 'International Reply Coupon - IRC'
The IRC was introduced by the UPU during its 1906 Congress held in Rome. It was created to facilitate mailings sent between foreign countries that required the receiver to reply, but the sender was unsure as to how much postage would be required for the reply letter.