A currency is a kind of money and medium of exchange. Currency includes paper, cotton, or polymer banknotes and metal coins. States generally have a monopoly on the issuing of currency, although some states share currencies with other states. For the purposes of this list, only currencies that are legal tender, including those used in actual commerce or issued for commemorative purposes, are considered "circulating currencies". Currencies used by non-state entities, like the Sovereign Military Order of Malta, scrips used by private entities, and other private and alternative currencies are not under the purview of this list.