What is a key characteristic of a mortise lock?

A mortise lock is defined by its specific design that requires a pocket, or mortise, to be cut into the door. This characteristic allows the lock mechanism to fit entirely within the routed opening, which provides a cleaner aesthetic and enhanced security compared to surface-mounted locks. The installation of a mortise lock also often includes a deadbolt feature, making it a robust option for doors. The flush placement within the door’s structure contributes to both the strength and functionality of the lock, as it is less susceptible to tampering than external locks.

The other choices do not capture the defining aspects of a mortise lock. A mortise lock does not use a simple key mechanism; in fact, it can accommodate more complex mechanisms. Additionally, mortise locks are known for their durability rather than lacking it, as they are designed to withstand significant wear and resistance against forced entry. Finally, mortise locks are predominantly used on doors rather than windows, which are typically equipped with different locking mechanisms better suited for their structural requirements.