A commemorative stamp is a postage stamp

Postage stamp

A postage stamp is a small piece of paper that is purchased and displayed on an item of mail as evidence of payment of postage. Typically, stamps are made from special paper, with a national designation and denomination on the face, and a gum adhesive on the reverse side...

, often issued on a significant date such as an anniversary, to honor or commemorate a place, event or person. The subject of the commemorative stamp is usually spelled out in print, unlike definitive stamp

Definitive stamp

A definitive stamp is a postage stamp, that is part of a regular issue of a country's stamps available for sale by the postal service for an extended period of time...

s 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

First day of issue

A First Day of Issue Cover or First Day Cover is a postage stamp on a cover, postal card or stamped envelope franked on the first day the issue is authorized for use within the country or territory of the stamp-issuing authority. Sometimes the issue is made from a temporary or permanent foreign or...

 ceremonies at locations connected with the subjects.