The term 'BILL STAMP' is used to refer to a stamp that is used to indicate that a bill has been PAID, is DUE, or is past DUE. The four crossword solutions for this term are PAID (4 letters), DUE (3 letters), SEAL (4 letters), and PASTDUE (7 letters). The PAID solution indicates that the bill has been PAID, the DUE solution indicates that the bill is DUE, the SEAL solution indicates that the bill has been sealed, and the PASTDUE solution indicates that the bill is past DUE.