Coin error collecting has its own specialized vocabulary. Understanding these terms is essential for communicating with other collectors, reading reference materials, and accurately describing your finds. This glossary covers the major terms used in error coin collecting, from common types to technical manufacturing terms.
Error coin terminology comes from the intersection of numismatics (coin collecting) and manufacturing (coin production). Many terms describe specific production failures, while others describe the physical characteristics of error coins. Learning this vocabulary helps you participate in the error coin community, understand listings and auction descriptions, and accurately identify your own finds.
Knowing the correct terminology helps you price and sell error coins effectively. Accurate descriptions using proper terms build buyer confidence. Misusing terminology can lead to miscommunication and pricing errors. The glossary terms above represent the core vocabulary every error coin collector should know.
Upload a photo of your coin or currency and let ErrorHunt's AI scanner check for errors in seconds.
Scan NowAn error is an unintentional manufacturing defect (like an off-center strike). A variety is a recognizable die characteristic that may be unintentional (like a doubled die) or intentional (like a design change). The terms overlap in casual use.
The correct term is "doubled die" because it refers to a die that was doubled during the hubbing process. The die received multiple impressions, making it a "doubled" die. "Double die" is a common misnomer.
PMD stands for Post-Mint Damage — any damage or alteration that occurred after the coin left the mint. PMD is not collectible as an error because it did not happen during production.
The Blakesley effect is a characteristic weakness in the rim opposite a clip on a clipped planchet. It occurs because the missing metal reduces striking pressure at the opposite point. Its presence helps authenticate genuine clips.