1. the act, achievement, or sense of completing or resolving something. In psychotherapy, for example, a client achieves closure with the recognition that he or she has reached a resolution to a particular psychological issue or relationship problem.

2. one of the Gestalt principles of organization. It states that people tend to perceive incomplete forms (e.g., images, sounds) as complete, synthesizing the missing units so as to perceive the image or sound as a whole—in effect closing the gap in the incomplete forms to create complete forms. Also called law of closure; principle of closure. See also auditory closure; goodness of configuration; Prägnanz; visual closure.

3. more generally, the act of closing or the state of being closed.