keyhole

The hole in a lock where the key is inserted and turns.

Any small opening resembling the hole for a key in shape or function.

A circle cut out of a garment as a decorative effect, typically at the front or back neckline of a dress.

(carpentry) A hole or excavation in beams intended to be joined together, to receive the key that fastens them.

(engineering) A mortise for a key or cotter.

(lasers) A transient column of vapor or plasma formed when using high energy beams, such as lasers, for welding or cutting.

(metallurgy) A welding method in which a hole forms in the surface immediately ahead of the puddle in the direction of welding. The hole is filled as the weld progresses.

(basketball) The free-throw lane together with the circle surrounding the free-throw line; key.

(astronomy) A gravitational keyhole.