A commemorative stamp is a postage stamp, often issued on a significant date such as an anniversary, to honor or commemorate a place, event, person, or object. The subject of the commemorative stamp is usually spelled out in print, unlike definitive stamps which normally depict the subject along with the denomination and country name only. Many postal services issue several commemorative stamps each year, sometimes holding first day of issue ceremonies at locations connected with the subjects. Commemorative stamps can be used alongside ordinary stamps. Unlike definitive stamps that are often reprinted and sold over a prolonged period of time for general usage, commemorative stamps are usually printed in limited quantities and sold for a much shorter period of time, usually, until supplies run out.

A postage stamp is a small piece of paper issued by a post office, postal administration, or other authorized vendors to customers who pay postage. Then the stamp is affixed to the face or address-side of any item of mail—an envelope or other postal cover —which they wish to send. The item is then processed by the postal system, where a postmark or cancellation mark—in modern usage indicating date and point of origin of mailing—is applied to the stamp and its left and right sides to prevent its reuse. Next the item is delivered to its addressee.