from The Century Dictionary and Cyclopedia
- n. In lock-making, a safety-key which, when placed in its lock, may serve to prevent the use of a master-key or any other key from the opposite side of the door.
Sorry, no etymologies found.
We learn from Dr. Bédart that as early as 1804 an arrangement suggestive of the stop-key was in use in Avignon Cathedral.
Horatio Clarke, of Reading, Mass., applied for a patent covering a form of stop-key in 1877.