That part of a tally, formerly in the exchequer, which was kept by an officer in that court, the other, called the stock, being delivered to the person who had lent the king money on the account; called also counterstock
A counterfoil is the part of a cheque, ticket, or other document that you keep when you give the other part to someone else. the part of something such as a cheque or ticket that you keep as a record (counter- + foil (15-18 centuries) (from ; FOIL))