The United States dollar (sign: $; code: USD; also abbreviated US$), also referred to as the American dollar, is the official currency of the United States of America and its overseas territories. It is divided into 100 smaller units called cents or pennies.
The U.S. dollar is the currency most used in international transactions and is one of the world's dominant reserve currencies. Several countries use it as their official currency and, in many others, it is the de facto currency. It is also used as the sole currency in some British Overseas Territories (British Virgin Islands and Turks and Caicos).
Money is any object or record that is generally accepted as payment for goods and services and repayment of debts in a given country or socio-economic context. The main functions of money are distinguished as: a medium of exchange; a unit of account; a store of value; and, occasionally in the past, a standard of deferred payment. Any kind of object or secure verifiable record that fulfills these functions can serve as money.
Money originated as commodity money, but nearly all contemporary money systems are based on fiat money. Fiat money is without intrinsic use value as a physical commodity, and derives its value by being declared by a government to be legal tender; that is, it must be accepted as a form of payment within the boundaries of the country, for "all debts, public and private".
The money supply of a country consists of currency (banknotes and coins) and bank money (the balance held in checking accounts and savings accounts). Bank money usually forms by far the largest part of the money supply.