What is a sealed written contract that promises to pay a sum certain in money at a fixed future time called?

The correct answer is a bond. A bond is a specific type of sealed written contract that represents a promise to pay a specified sum of money at a designated future date. It often involves a lender providing funds to a borrower, with the expectation that the borrower will repay the principal amount along with any agreed-upon interest. This financial instrument is legally enforceable, and the terms are clearly outlined in the bond document.

Bonds are commonly used in various financial contexts, including government and corporate financing, as they serve as a guarantee to the bondholder that they will receive their money back at maturity, along with periodic interest payments if applicable. The structured nature and formal requirements, including being sealed, distinguish bonds from other types of agreements that may not have the same level of specificity regarding repayment and timing.