The United States dollar (symbol: $; code: USD; also abbreviated US$; referred to as the dollar, U.S. dollar, or American dollar) is the official currency of the United States and its territories per the Coinage Act of 1792. One dollar is divided into 100 cents (symbol: ¢), or into 1000 mills for accounting and taxing purposes (symbol: ₥). The Coinage Act of 1792 created a decimal currency by creating the dime, nickel, and penny coins, as well as the dollar, half dollar, and quarter dollar coins, all of which are still minted in 2020.
Several forms of paper money were introduced by Congress over the years, the latest of which being the Federal Reserve Note that was authorized by the Federal Reserve Act of 1913. While all existing U.S. currency remains legal tender, issuance of the previous form of the currency (U.S. notes) was discontinued in January 1971. As a result, paper money that is in current circulation consists primarily of Federal Reserve Notes that are denominated in U.S. dollars.Since the convertibility of paper U.S. currency into any precious metal was suspended in 1971, the U.S. dollar is de facto fiat money. Not only is the U.S. dollar the world's primary reserve currency as the most used in international transactions, it is the official currency in several countries and the de facto currency in many others. Aside from the United States itself, the American dollar is also used as the sole currency in two British Overseas Territories in the Caribbean: the British Virgin Islands and Turks and Caicos Islands. A few countries use the Federal Reserve Notes for paper money while still minting their own coins, or also accepting U.S. dollar coins (such as the Sacagawea or Presidential dollar). As of January 31, 2019, there is approximately US$1.7 trillion in circulation, $1.65 trillion of which is in the Federal Reserve Notes (the remaining $50 billion is in the form of U.S. notes and coins).The U.S. dollar as a currency is sometimes referred to as the greenback by foreign exchange traders and the financial press in other countries, such as Australia, New Zealand, South Africa, and India.