bill of exchange
(ECONOMICS) method of transferring wealth from a buyer to a seller, usually over long distances and under different currency systems. Requires the buyer to have an account with a banker in the other city; the buyer sends a note ordering his banker to credit the seller's account by the amount being paid.

Bills of exchange were adopted in 13th century Italy; almost as soon as they became common, traders began to use them as a speculative instrument (discounting bad ones and reselling them) or else as a sleazy method of borrowing money (by "drawing and redrawing," i.e., where two merchants in different towns agree to exchange bills of exchange with each other). "Drawing and redrawing" is analogous to the method used by college students on the 1980's of writing checks to each other every couple of days and depositing them in ATM's so their checking accounts wouldn't bounce.
A bill of exchange is a type of "negotiable instrument" (contractual form of money).

A modern form of bill would be a check.