Gold coins (aurum) are distinguished by the letters AV.
Electrum coins „ „ „ EL.
Silver coins (argentum) „ „ „ AR.
Bronze coins (aes) „ „ „ AE.
Billon and Potin coins (alloys of silver and bronze) by Bil. and Pot.
The disk of metal on which the types are struck is called the Flan.
The front or face of a coin is called the Obverse. Obv.
The back of the coin is called the Reverse. Rev.
The principal device represented on the obv. or rev. is called the Type.
Adjunct devices or secondary types are called Symbols.
The area or space between the type and the circumference is called the Field.
The lower portion of the area beneath the type and cut off from the rest of the field by
a horizontal line is called the Exergue.
Portions of a coin which are sunk below the level of the surface of the field are said to
be Incuse.