: something which a person makes up himself. A mock-up is morehan a mental picture; it is a self-created image a person can see and exists as itself, or symbolizes some object in the physical universe. The term was derived from the World War II phrase for miniature models that were constructed to symbolize weapons (airplanes, ships, artillery, etc.) or areas of attack (hills, rivers, buildings, etc.) for use in planning a battle. Mock up is also used to simply mean "create." —PDC Volume 8 Approved Glossary