The term mortgage has its roots in a French legal term used in Great Britain during the Middle Ages. This term, which translates to “promise of death”, was used to refer to a promise that would end when the obligation was fulfilled or the property was acquired through foreclosure. The word itself is derived from Old French morgage, literally meaning “dead garment”, from mort (dead) and gage (garment). According to the online etymology dictionary, it is so called because the transaction ends when the debt is paid or when the payment fails.
The term mortgage is also derived from Middle English Morgage and Half French Mortgage, from Anglo-Norman Morgage, from Old French Mort Gage (“promise of death”). This is according to a translation from medieval judicial Latin mortuum wadium, from mortuum + wadium, from Franco-*wadi (“bet, promise”). It is so called because the agreement ends when the debt is paid or when the payment fails.