Definition: A commemorative coin, in U.S. coin collecting, is usually understood to be one of the special non-circulating coins issued by the U.S. Mint, and which are sold to collectors at prices substantially above face value, and which include surcharges that support a program related to the subject of the coin. For example, part of the purchase price of the San Francisco Old Mint commemorative coins went to fund the establishment of a museum in the S.F. Old Mint building.
In a more general sense, especially in non-U.S. coins, a commemorative coin is a circulating coin that commemorates a certain person, place, or event. Commemoratives are usually only issued for one year, although they are sometimes extended, and they are characterized by the fact that they deviate from the "normal" or regular issue coins.
Sometimes commemorative coins end up becoming regular coins, as in the case of the U.S. Lincoln Cent and Washington Quarter. Both coins, when first issued, were meant to be one-year circulating commemoratives, but the public liked them so much that the Mint continued issuing them.
In a more general sense, especially in non-U.S. coins, a commemorative coin is a circulating coin that commemorates a certain person, place, or event. Commemoratives are usually only issued for one year, although they are sometimes extended, and they are characterized by the fact that they deviate from the "normal" or regular issue coins.
Sometimes commemorative coins end up becoming regular coins, as in the case of the U.S. Lincoln Cent and Washington Quarter. Both coins, when first issued, were meant to be one-year circulating commemoratives, but the public liked them so much that the Mint continued issuing them.
Examples:
When most people think of commemorative coins, they think of the specially-struck non-circulating coins sold at a premium by the U.S. Mint, which are meant to raise funds for a particular purpose.