Definition of 'Currency'
A generally accepted form of money, including coins and paper notes, which is issued by a government and circulated within an economy. Used as a medium of exchange for goods and services, currency is the basis for trade.
Investopedia explains 'Currency'
Generally speaking, each country has its own currency. For example, Switzerland's official currency is the Swiss franc, and Japan's official currency is the yen. An exception would be the euro, which is used as the currency for several European countries.
Investors often trade currency on the foreign exchange market, which is one of the most heavily traded markets in the world.