Enter a clue or pattern or both:
The Clue
Commitment to pay (3 letter answer)
The Answer
IOU
Tags
Notes
The answer IOU is seen frequently, appearing about once every 90 puzzles.
Related Clues
Chit
Marker
Note
Promise
Bettor's note
Bill, of a sort
Cash substitute
Debt acknowledgment
Debt doc
Debt marker
Debtor's letters
Debtor's note
Gambler's mark
Letters on a chit
Letters of credit
Letters of credit?
Marker letters
Marker, of sorts
Paper in a pot
Payment promise
Promise to pay
Promise of payment
Promissory note
Slip in a pot
Indicator of shortness, for short
Item in a poker pot
Letters from a short person?
Marker in a poker pot
Note traded for bills
Paper in lieu of payment
Promissory note of a sort
Last poker bet, sometimes
Note to be used later
Poker game memento, maybe
Definition
IOU as a noun:
1. an informal debt instrument; representing `I owe you'