[wikipedia] used either by purchasers of real property to raise funds to buy real estate; or alternatively by existing property owners to raise funds for any purpose, while putting a lien on the property being mortgaged
[dictionary] The usual way of calculating interest - as a percentage of the sum borrowed.
[mtgprofessor] how many years the borrower has to repay the mortgage
Adjustable Rate Mortgage
[investopedia] A mortgage on which the interest rate, after an initial period, can be changed by the lender.
Fixed Rate Mortgage
[bankrate] A mortgage in which the interest rate does not change throughout the term