One US dollar is the basic unit of currency in the United States, represented by the symbol $. It is subdivided into 100 smaller units called cents. The dollar is issued by the $U.S. Department of the Treasury and is used for various transactions, both domestically and internationally. The dollar is also a key component of the global economy, often serving as a reserve currency for many countries. It is widely accepted in international trade and is used as a benchmark for valuing other currencies, making it an essential part of the $foreign exchange market.