The most widely used currency in the world is the United States dollar (USD). It is the primary medium of exchange for international trade, held as the world's dominant reserve currency. Many countries use the USD in addition to their own national currencies, a practice known as dollarization. The dollar's popularity stems from the economic stability of the United States and its influence on global markets. Furthermore, commodities like oil and gold are often priced in USD, reinforcing its role and demand in international finance.