A mortgage is a loan that is used to purchase a piece of real estate, such as a house or an apartment building. The property that is purchased serves as collateral for the loan, and the borrower is required to make regular payments to the lender to repay the loan. Mortgages are typically long-term loans, with repayment periods that can range from 15 to 30 years. The terms of the mortgage, such as the interest rate and the monthly payment amount, are typically determined based on the borrower's creditworthiness and the value of the property. Mortgages can be a useful tool for people who want to buy a property but do not have the cash to pay for it upfront.