The word “amortization” refers to the process of paying off your mortgage, where the interest is paid first and the principal last. The word amortize comes from the Old French word “amortiser,” which means “to kill off.” Recognize the word “mort” in there — as in mortuary, mortal, and mortgage? Amortize was first used in the 16th century in reference to religious orders and their practice of gradually buying back land and property that had been pledged as collateral for loans. Over time, the concept was applied to finance and real estate.