Money is a medium of exchange for goods and services. It is money, in the form of paper or coin, usually issued by a government and generally accepted at face value as a form of payment.
Money is the primary medium of exchange in the modern world, having long since replaced barter as the means of exchanging goods and services. In the 21st century, a new form of money has entered the vocabulary, virtual money. Virtual currencies such as Bitcoin have no physical existence or government backing and are traded and stored in electronic form.
A key feature of modern money is that it is uniformly worthless in itself. That is, bills are pieces of paper rather than coins made of gold, silver or bronze. The acceptance of a piece of paper in exchange for real value has been slow to take hold.
