A mortgage loan is a crucial financial instrument that allows individuals and businesses to purchase real estate or raise funds by using their property as collateral. This "secured" loan, sometimes known as a hypothec, grants the lender a legal claim (lien) on the property, enabling them to take possession and sell it through "foreclosure" if the borrower defaults; its name derives from the medieval Law French term "death pledge."

Typically provided by financial institutions such as banks, mortgages are fundamental to homeownership worldwide, as most people lack sufficient liquid funds to buy property outright. A key feature is the lender's priority over other creditors if the borrower faces bankruptcy. These loans are commonly structured with interest rates and amortized over fixed periods, such as 30 years in the United States.