Exonumia
The noun Exonumia is from two classic roots: Exo, or out-of, and Numis, numismatically (coin) related, thus Out-of-coins. It covers coin-like objects such as token and medals, and other items used in place of legal currency or for commemoration, including elongated coins, encased coins, souvenir medallions, tags, badges, counterstamped coins, wooden nickels, credit_cards, as well as other similar items. It is related to numismatics, and many coin collectors are also exonumismatists.The famous stone "coins" of Yap, Chinese hoe and knife money and large plate money are among the more interesting examples of exonumia. Siege coins (obsidional money) is another interesting area of exonumia. The earliest paper money was produced by stamping hymnals and other books during a siege in Leyden in 1574. Currency as we know it was first used in 1793 during the sieges of Lyons, Mayence, and Vendee. Even playing cards were at times used for money.