A bill of exchange issued by the government and payable in three months. They are issued by tender every week in very large amounts and discount houses make offers, quoting prices. Rates of interest are usually very low. By far the greatest number of bills dealt with by discount houses are treasury bills; discount houses sometimes sell to the clearing banks, but the banks never tender directly. Treasury bills are sometimes allotted to central banks of other countries.
Reference: The Penguin Business Dictionary, 3rd edt.