Bill-exchange, also known as a negotiable instrument, refers to a financial document that guarantees payment from one person or institution to another. Other synonyms for bill-exchange include promissory note, draft, check, and cashier's order. All of these financial instruments serve the same purpose, which is to provide legal proof of an agreement between two parties and facilitate the transfer of funds. While the terminology may differ, the underlying concept remains the same. By utilizing these financial tools, individuals and businesses can conduct transactions with confidence and transparency, knowing that the terms of their financial agreement are legally binding and enforceable.