I owe you
I owe you (noun) means a signed note acknowledging a debt, usually written informally and stating what is owed rather than when it will be repaid; normally written IOU. Example: “He left an IOU for twenty pounds under the biscuit tin.”
How to use I owe you
Learner’s notesIn plain EnglishA note saying you owe someone money, or a way of saying you will return a favour.
IOU is neutral in financial contexts; I owe you one is casual spoken English.
Fill the gap
Can you complete this real example?
Thanks for covering my shift, _____ one.
Etymology
The noun IOU is a spelling of the spoken phrase I owe you using the sounds of the three letters.