- a written acknowledgment of a debt, especially an informal one consisting only of the letters IOU, the sum owed, and the debtor's signature.
Origin of IOU
First recorded in 1610–20; representing I owe you
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
- a written promise or reminder to pay a debt
C17: representing I owe you
Word Origin and History for i.o.u.
also IOU, I O U, 1610s, originally as IOV (see V); with punning reference to "I Owe You."
Online Etymology Dictionary, © 2010 Douglas Harper
The New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.