- I.O.U
- A memorandum of debt, consisting of the three letters, "I.O.U.," a statement of the amount, and debtor's signature, constituting an instrument for the unconditional payment of money only, and, according to some but not all the authorities, a promissory note. 11 Am J2d B & N § 140.
Ballentine's law dictionary. Anderson, W.S.. 1998.