Keyhole n. : A hole or apertupe in a door or lock, for receiving a key.

Keyhole n. : A hole or excavation in beams intended to be joined together, to receive the key which fastens them.

Keyhole n. : a mortise for a key or cotter.

Example:
How do I repair the Keyhole on my driver side door of my truck?

Taxonomy
Keyhole, free encyclopedia, small body, Keyhole surgery, gravitational, Keyhole cichlid, search, free dictionary, lock, meanings, orbit, company, Google, comic, the 1990s, KH, satellites, United States.

Defination from the web:
keyhole is a region of an orbit where a small gravitational input could cause a small body to collide with the large body it is orbiting. ... Keyhole cichlid, a fish from the genus Cleithracara. Keyhole button closure, is a single button, usually found on the back of a ...