Treasury Notes
These are nots issued by the government of the United States, and pay interest to the holders every 6 months. These interest rates are always fixed, and they mature within 10 years (sometimes as short as 1 year). Also referred to as simply T-Notes, they are traded heavily on the secondary market. This means that they can be purchased directly from the US Government, or through other secondary exchangers.
Treasury fixed-principal bonds issued with a stated rate of interest to be applied to their par amount, having interest payable semiannually, and redeemed at their par amount at maturity. They typically have maturities of more than 10 years.