Click

A click refers to the action of pressing and releasing a button on a mouse, trackpad, or other pointing device. This generates an event, also the pointer's position on the display, which is processed by the window manager or application program.

Actions
On a mouse with more than one button, the unqualified term usually implies pressing the left-most button (e.g. "left-click" with the right-hand index finger). Multiple clicks in quick succession (e.g. "double-click") will usually trigger a different action than a single click, such as opening a file instead of just selecting it. If the mouse or pointing device is moved while the button is pressed, then this is referred to as a drag.

Keyboard modifiers, such as the Shift key, may also be held down while clicking to enable alternate actions, such as selecting multiple items. Since early Macs usually came with a single-button mouse, holding down the Control key while clicking would enable similar features as a "right-click", such as contextual menus.