U.S. Treasury Bonds – US Treasury bonds are backed by the full faith and credit of the United State government. When the government spends more than it collects in taxes and other revenues, it issues Treasury notes, bills, and bonds to borrow the money to pay the difference. Treasury bonds have the longest term or period of time before the loan must be repaid (10 years or more). Treasury bills have the shortest (less than two years).
(URL) Stock Market Glossary: U.S. Treasury Bonds