A rim lock is a type of lock that is mounted on the surface of a door rather than being installed inside a mortise like a mortise lock. It is typically attached to the inside face of the door and secured with screws that pass through the door and into the lock body.
Rim locks are often used in residential settings and can be found on both interior and exterior doors. They typically have a latch bolt that is operated by a key or a thumb turn on the inside of the door, and may also have a deadbolt for added security.
One of the advantages of rim locks is that they are easier to install than mortise locks since they don't require a mortise to be cut into the door. They are also easier to repair or replace if necessary. However, they may be less secure than mortise locks since they are mounted on the surface of the door and can be more vulnerable to forced entry or tampering.