The New International Encyclopædia/I. O. U.

I. O. U. (I owe you ) . A memorandum of debt or due bill, named from its abbreviated form, viz.:

New York, January 1, 1903. 

 John Doe, I. O. U. $20.

Richard Roe. 

In England and in most of our States, it is not treated as a promissory note (q.v.) because it does not contain an express promise to pay. By statute or by judicial decisions in some States an I. O. U. is declared to be a promissory note. See Due Bill.