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or I.O.U

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 Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2018.
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British Dictionary definitions for i.o.u.


a written promise or reminder to pay a debt
Word Origin
C17: representing I owe you
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
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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
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i.o.u. in Culture

IOU definition

Abbreviation for “I owe you.” An IOU is a written statement of a borrower's obligation to pay a debt.

The New Dictionary of Cultural Literacy, Third Edition
Copyright © 2005 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
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Slang definitions & phrases for i.o.u.



A promise to pay; written acknowledgment of a debt: had won $800,000, in cash, not IOUs (1618+)

The Dictionary of American Slang, Fourth Edition by Barbara Ann Kipfer, PhD. and Robert L. Chapman, Ph.D.
Copyright (C) 2007 by HarperCollins Publishers.
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