A long-term promissory note issued by the United States government for terms of 10 to 30 years and backed by the full faith of the United States government. Because they are considered to be risk-free, they carry the lowest taxable yield of any bonds. They are sold at a discounted rate and attain full face value upon maturity. See also treasury bill and treasury note. Treasury Department, United States n. The United States Treasury Department's basic functions are to develop and propose natio...