i.o.u
  借據
  I O U, I.O.U  A paper having on it these letters, with a sum named, and duly signed; -- in use in England as an acknowledgment of a debt, and taken as evidence thereof, but not amounting to a promissory note; a due bill.
  ◄ ►
  IOU
       n : an informal debt instrument; representing `I owe you'