IOU

American  

Or I.O.U.

1. a written acknowledgment of a debt, especially an informal one consisting only of the letters IOU, the sum owed, and the debtor's signature.

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IOU British  

noun

1. a written promise or reminder to pay a debt

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IOU Cultural  

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

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Etymology

Origin of IOU

First recorded in 1610–20; representing I owe you

Example Sentences

Essentially, you borrow from the account and create an IOU to yourself.

From MarketWatch • Jan. 14, 2026

Credit is the promise to pay money, an IOU.

From The Wall Street Journal • Dec. 12, 2025

If the players acknowledge the worth of the IOU and its holder bets it as if it were cash, it must be accepted at face value by the pot’s winner.

From The Wall Street Journal • Nov. 6, 2025

But, on paper, Trimpley immediately appeared to be worth £3bn because it had the IOU.

From BBC • Dec. 9, 2024

Since I can’t afford to buy Dad that engraved picture frame until Mrs. Gilbert can afford to pay me, I decide to give him a handmade IOU.

From "Shine!" by J.J. and Chris Grabenstein