Money is any object that is generally accepted as payment for goods and services and repayment of debts in a given socioeconomic context or country. Money comes in three forms: commodity money, fiat money, and fiduciary money.
Many items have been historically used as commodity money, including naturally scarce precious metals, conch shells, barley beads, and other things that were considered to have value . The value of commodity money comes from the commodity out of which it is made. The commodity itself constitutes the money, and the money is the commodity.
Commodity Money
Conch shells have been used as commodity money in the past. The value of commodity money is derived from the commodity out of which it is made.
Fiat money is money whose value is not derived from any intrinsic value or guarantee that it can be converted into a valuable commodity (such as gold). Instead, it has value only by government order (fiat). Usually, the government declares the fiat currency to be legal tender, making it unlawful to not accept the fiat currency as a means of repayment for all debts. Paper money is an example of fiat money.
Fiduciary money includes demand deposits (such as checking accounts) of banks. Fiduciary money is accepted on the basis of the trust its issuer (the bank) commands.
Most modern monetary systems are based on fiat money. However, for most of history, almost all money was commodity money, such as gold and silver coins.
Functions of Money
Money has three primary functions. It is a medium of exchange, a unit of account, and a store of value:
- Medium of Exchange: When money is used to intermediate the exchange of goods and services, it is performing a function as a medium of exchange.
- Unit of Account: It is a standard numerical unit of measurement of market value of goods, services, and other transactions. It is a standard of relative worth and deferred payment, and as such is a necessary prerequisite for the formulation of commercial agreements that involve debt. To function as a unit of account, money must be divisible into smaller units without loss of value, fungible (one unit or piece must be perceived as equivalent to any other), and a specific weight or size to be verifiably countable.
- Store of Value: To act as a store of value, money must be reliably saved, stored, and retrieved. It must be predictably usable as a medium of exchange when it is retrieved. Additionally, the value of money must remain stable over time.
Economists sometimes note additional functions of money, such as that of a standard of deferred payment and that of a measure of value. A "standard of deferred payment" is an acceptable way to settle a debt--a unit in which debts are denominated. The status of money as legal tender means that money can be used for the discharge of debts. Money can also act a as a standard measure and common denomination of trade. It is thus a basis for quoting and bargaining prices. Its most important usage is as a method for comparing the values of dissimilar objects.