the action of a computer user moving a pointer to a certain location on a screen (point) and then pressing a mouse button, usually the left button (click)
One of the core components of the WIMP (Windows, Icons, Menus and Pointers) interaction, the pointer is an onscreen symbol that represents movement of a physical device that the user controls to select icons, data elements, etc.
The actions performed by the pointer are: moving and selecting. The act of selecting done by the pointer (usually a mouse) is termed as 'click'.
Questions having the click tag regards the User Experience of a click action