means A long-term loan used to buy property, secured against that property, which the lender can seize if you stop paying.

from Straight from Old French: 'mort' (dead) plus 'gage' (pledge) — literally a 'dead pledge.' The 14th-century legal reasoning, explained by the English jurist Coke, was elegantly grim: the pledge 'dies' either way — if the debt is paid, the pledge is dead to the lender; if it isn't, the property is dead to the borrower. 'Mort' traces back to Latin 'mors/mortem' (death), the same root behind mortal and mortuary; 'gage' is a Germanic borrowing related to 'wage' and 'engage.' The silent 't' is a fossil of that French parentage.