From Longman Dictionary of Contemporary Englishmortise lockˈmortise lock noun [countable] British English DTa strong lock that fits into a hole cut in the edge of a door SYN dead bolt American English
Examples from the Corpus
mortise lock• It had a mortise lock, a simple keyhole and no key.• Fit a five-lever mortise lock to the back door, or supplement the existing lock with a mortise deadlock.Origin mortise lock (1700-1800) mortise “hole made for a part to fit into” ((14-21 centuries)), from Old French, probably from Arabic murtaj “locked” 