(a) Authority shall mean the New York State Bridge authority.

(b) Contract shall mean an enforceable agreement entered into by the authority and a contractor, including purchase orders.

(c) Contractor shall mean any persons or organizations providing goods, property or services to the authority pursuant to a contract.

(d) Designated payment department shall mean that department within the authority to which a proper invoice is to be submitted by a contractor.

(e) Prompt payment shall mean payment of a debt due and owing to the authority before interest accrues thereon pursuant to the specifications herein.

(f) Proper invoice shall mean a written request for contract payment setting forth the description, price and quantity of goods, property or services provided by a contractor in such form, and supported by such other substantiating documentation, as the authority may reasonably require.

(g) Receipt of an invoice shall mean either (1) the date on which a proper invoice is received by the designated payment department, or (2) the date on which the authority receives the purchased goods, property or services covered by the proper invoice, whichever is later.

(h) Set-off shall mean the reduction by the authority of a payment due to a contractor by an amount equal to the amount of an unpaid legally enforceable debt owed by the contractor to the authority.