Meaning & use
IOU
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Meanings
nouncountableinformal
A short signed note saying that you owe someone money and will pay it back.
Grammar: Takes a plural, IOUs; common for small personal loans rather than contracts.
Patterns
- sign an IOU
- owe someone an IOU
- pay back an IOU
I lent Sam forty dollars and asked him for an IOU.
She keeps every IOU in a drawer so she remembers who still owes her money.
He wrote an IOU on the back of an envelope after borrowing cab fare.
nouncountablebusinessfinance
In business records, an informal written acknowledgment that money is owed rather than received.
Grammar: Used in loose accounting or notes; use debt or liability for precise documents.
Patterns
- issue an IOU
- record an IOU
- an IOU from a customer
The shop logged the missing payment as an IOU from a regular customer.
At year-end, the manager converted every IOU into a proper invoice.
The club treated donated supplies as an IOU until cash came in.
Common combinations
- sign an IOU
- He refused to sign an IOU for such a small amount.
- owe someone an IOU
- I owe you an IOU for lunch last week.
- pay back an IOU
- She paid back the IOU as soon as her paycheck arrived.
- issue an IOU
- The treasurer issued an IOU when the cash box was empty.
Synonyms and how they differ
- promissory note
- More formal and usually stronger legally; an IOU is shorter and often casual.
- IOU note
- Clarifies the informal paper itself, but IOU already names the same idea.
Word family
Commonly confused: IOU or I owe you? IOU or invoice?
IOU vs I owe you
IOU comes from this phrase, but write it as the capital letters when naming the note.
IOU vs invoice
An invoice asks for payment for goods or services; an IOU admits that payment is owed.
Practice
After borrowing $20 from a friend, the most natural informal promise is ___ .
Choose one answer.
An IOU is an informal written promise to repay a debt. A receipt shows payment already happened, an invoice requests payment from a customer, and a check would pay immediately rather than promise later.
Make it your own
Write a sentence using “IOU”, then check it and compare it with the examples above.