Currency relative values of the different currencies. Currencies in this sense are defined by governments, and each type has limited boundaries of acceptance. Other definitions of the term "currency" are discussed in their respective synonymous articles banknote, coin, and money. The latter definition, pertaining to the currency systems of nations, is the topic of this article. Currencies can be classified into two monetary systems: fiat money and commodity money, depending on what guarantees the value (the economy at large vs. the government's physical metal reserves). Some currencies are legal tender in certain political jurisdictions. Others are simply traded for their economic
Currency substitution rate. Currency substitution increases with inflation volatility and decreases with the volatility of the real exchange rate. The flight from domestic money depends on a country's institutional factors. The first factor is the level of development of the domestic financial market. An economy with a well-developed financial market can offer a set of alternative financial instruments denominated in domestic currency, reducing the role of foreign currency as an inflation hedge. The pattern of the currency substitution process also varies across countries with different foreign exchange and capital controls. In a country with strict foreign exchange regulations, the demand for foreign