"Keyway" redirects here. For the defunct airline, see Keyway Air Transport. For other uses, see Keyhole (disambiguation).
A keyhole (or keyway) is the shaped channel in a lock cylinder into which the key slides to gain access to the lock tumblers. 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.