a written account of ownership or obligation

a highly liquid debt instrument with maturities of less than three months

a debt instrument issued by a bank; usually pays interest

a promise to pay a specified amount on demand or at a certain time

a debt instrument with a variable interest rate tied to some other interest rate (e.g. the rate paid by T-bills)

a certificate of debt (usually interest-bearing or discounted) that is issued by a government or corporation in order to raise money; the issuer is required to pay a fixed sum annually until maturity and then a fixed sum to repay the principal