Keyway
From Wikipedia, the free encyclopedia
A keyway is the shaped channel in a lock cylinder into which the key slides to gain access to the lock tumblers.
A keyway is also a longitudinal slot milled along the side of a cylindrical machine shaft, or a notch cut into the inside hole of a pulley or gear, all of which indentations are intended to accept a small rectangular bit of metal -- a key -- which is one way of locking pulleys, gears, and other parts to shafts.
Lock keyway shapes vary widely with lock manufacturer, and many manufacturers have a number of unique profiles requiring a specifically milled key blank to engage the lock's tumblers.
Most people refer to lock keyways as keyholes, a linguistic carryover from the days when locks utilized bit keys that actually entered the lock through a hole in the door.