Definition: Mortgage is an interest-bearing loan, typically for home ownership. The term mortgage was first used in the United States by Wall Street investors to refer to investments made on behalf of clients. In later years, it has been used more generally to refer to any financial commitment that involves a debt obligation or promise to repay the principal amount of a loan. This loan is usually secured (guaranteed) with a mortgage deed and typically allows the borrower to use the funds for mortgage payments, home improvements, or other purposes.