Bond is a long-term debt instrument issued by a corporation or a government. It is a fixed-income security.A bond is a formal contract to repay borrowed money with interest at fixed intervals. Generally it is a debt investment in which an investor loans money to an entity which borrows the funds for a defined period of time at a variable or fixed interest rate. A bond, also known as a fixed-income security, is a debt instrument created for the purpose of raising capital.