<p><strong>Noun</strong></p><ul><li>A hole for inserting a key in a lock</li><li>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</li><li>Also called key</li><li>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</li></ul><p><strong>Adjective</strong></p><ul><li>Extremely private or intimate, especially with reference to information gained as if by peeping through a keyhole</li><li>Snooping and intrusive: a keyhole investigator</li></ul>