Currency is a medium of exchange for goods and services. In short, it’s money, in the form of paper or coins, usually issued by a government and generally accepted at its face value as a method of payment.
Currency is the primary medium of exchange in the modern world, having long ago replaced bartering as a means of trading goods and services.
In the 21st century, a new form of currency has entered the vocabulary, the virtual currency. Virtual currencies such as BITCOINS have no physical existence or government backing and are traded and stored in electronic form.