- a hole for inserting a key in a lock, especially one in the shape of a circle with a rectangle having a width smaller than the diameter of the circle projecting from the bottom.
- Also called key. Basketball. the area at each end of the court that is bounded by two lines extending from the end line parallel to and equidistant from the sidelines and terminating in a circle around the foul line.
- extremely private or intimate, especially with reference to information gained as if by peeping through a keyhole.
- snooping and intrusive: a keyhole investigator.
- an aperture in a door or a lock case through which a key may be passed to engage the lock mechanism
- any small aperture resembling a keyhole in shape or function
- a transient column of vapour or plasma formed during the welding or cutting of materials, using high energy beams, such as lasers