The box on a door-jamb into which the bolt of a lock protrudes when shot.(noun)
The Century Dictionary (Public Domain)
Use "lock-keeper" in a sentence
"Wife of the Britannia lock-keeper, I learned she was."
"There's just enough room on this one for the lock-keeper's house, his beautifully kept garden and a small copse, one part of which is the tiny, five-pitch campsite."
"Several of the locks on the upper reaches of the Thames are home to small, simple campsites overseen by the lock-keeper, often accessible only by boat or on foot."