Mortgage is a French word. It’s a combination of two Old French words, mort meaning “death” and gage meaning “pledge.” Yep, signing a mortgage means you are signing a death pledge. It was named this as a mortgage only ends when the loan has been paid off, or when you die. So if you are of the age when you are thinking about getting a mortgage, please don’t let this grizzly etymology sway your decision.
Patrick Foote, The Origin of Names, Words, and Everything Between.