Alloy: A mixture of two or more metals. The mixture usually will make a coin inexpensive to produce.

Bullion: A metal slab that has not been made into a coin.

Commemorative Coin: A coin that is made for an important event or person. Sometimes this coin will be placed into circulation.

Condition: What a coin looks like. This is helpful, so a value can be placed on it.

Cull: A coin that is in very poor shape. Most of the time, it is very well worn. Also known as a "filler" coin.

Die: A metal device that is used to put the design on a coin.

Double Strike: What happens when a die strikes a coin more than once. Also called a double die error.

Face Value: The denomination of a coin. Example: one cent, five cents, etc.

Grading: A process used to determine a coin's condition. A numerical and adjective scale is used for this process.

Key Date: A coin that is rare and had low mintages. This type of coin usually completes a coin collection.

Legend: The wording that is found on a coin.

Market Value: The price that a coin will sell to a collector.

Milled Edge: A raised edge of a coin. Usually referred to as a rim.

Mint Mark: A small letter placed on to a coin to determine where it was minted.

Module: The diameter of a coin.

Numismatics: The science of metals and coins.

Obverse: The front side of a coin, usually the head side. The date is mostly found here with the main design.

Patina: The green color found on copper coins usually caused by oxidation.

Pattern: A sample coin that could be used for circulation.

Planchet: A blank piece of metal used to receive a coin stamp.

Premium Value: The price paid for a coin beyond it's face value.

Proof: A coin with a mirror like surface that has not been touched by human hands. These coins are not in circulation, and are only made for coin collectors.

Reeded Edge: A coin with a rough edge. Example: The Washington quarter dollar.

Reverse: The back side of a coin, usually called "tails".

Roll: A group of coins usually the same type, date, mint, and denomination.

Semi Key Date: A coin that is moderatly rare and minted.

Type Collecting: A set of coins with the same design. Example: Jefferson nickels.

Up Grading: A process coin collectors do when replacing lower graded coins with higher graded coins.