A dollar bill is a form of paper currency used in the United States, representing one unit of the U.S. dollar. It is issued by the Federal Reserve and features various security measures to prevent counterfeiting. The front side of the bill typically displays a portrait of a prominent figure, such as George Washington, while the back side features a design that reflects American history or symbols. Dollar bills are widely accepted for transactions and can be used to purchase goods and services. They are part of a larger system of currency that includes coins and higher denominations, facilitating everyday commerce in the economy.