Amortization – paying your mortgage off over time, with some portion of your loan payments going to pay interest charges, and some portion going to pay the principal loan amount (i.e., the amount you owe) off.  Mortgages can be fully amortized (meaning that some portion of every payment goes to pay principal), interest-only (meaning that for at least some period of time, the minimum payment does not pay any of the principal off), or negatively amortized (meaning that the minimum payment pays even less than the interest being charged on the loan, so that the principal balance actually increases)