legal tender coins or medallions usually minted of gold or silver to commemorate themes, events, places, or people.

Stamps that honor anniversaries, important people or special events.

issued in observance of historical events in honor of noted Americans and on topics of national importance. Each commemorative issue is printed in limited quantities to be sold for a limited period of time (usually 60 days). Commemoratives are usually larger and more colorful than definitives. Only a limited number of each commemorative is printed, and most post offices only have them for a few months. The U.S. Postal Service's Philatelic Fulfillment Service Center also offers commemorative stamps by mail order for about one year after they are issued.

Stamps that honour anniversaries, important people or special events.