I.O.U.
I believe the answer is:
chit
(Other definitions for chit that I've seen before include "bill to pay" , "Short note of money owed or received" , "Tab" , "Note - voucher" , "Short official note recording a sum owed" .)
I believe the answer is:
chit
(Other definitions for chit that I've seen before include "bill to pay" , "Short note of money owed or received" , "Tab" , "Note - voucher" , "Short official note recording a sum owed" .)