Mortise locks are ______ the frame of a door and used when a door knob or latch are required for entry.

• A. Mounted on
• B. Hidden behind trim
• C. Recessed into
• D. Attached to the door frame

Answer: (C)

Mortise locks are designed to sit inside a pocket cut into the door itself, so the lock mechanism is recessed into the door rather than mounted on its surface. This flush, integrated installation is what gives mortise locks their strength and a cleaner appearance, especially when a door knob or lever is needed for entry and security is a priority. The frame merely hosts the strike plate that the latch or bolt engages, not the lock body itself.

Options that suggest the lock sits on or behind the trim, or that it attaches to the frame, don’t match how mortise locks are installed, since the key hardware is embedded in the door.