A mortise lock is a type of locking mechanism that is typically used for doors. It is installed inside a mortise, which is a hole or recess that is cut into the edge of the door. The mortise lock consists of a lock body that is inserted into the mortise, along with a lock cylinder, a latch or bolt mechanism, and sometimes a handle or knob.
Mortise locks are often used in commercial or high-security applications because they offer greater durability and strength than other types of locks. They are also more resistant to forced entry and tampering. However, they can be more difficult to install and maintain than other types of locks and may require the services of a professional locksmith.