Click

Press and release the left mouse button, without moving the mouse.

Left-click

Same as click. The term 'left-click' is used where there might be confusion with right-click.

Middle-click

Press and release the middle mouse button, without moving the mouse.

Right-click

Press and release the right mouse button, without moving the mouse.

Double-click

Press and release the left mouse button twice in rapid succession without moving the mouse. You can configure the sensitivity to double-clicks by changing the Double-click Timeout setting: see the section called Mouse Preferences for more information.

Drag

Press and do not release the left mouse button, and then move the mouse with the button still held down, and finally release the button.

Dragging with the mouse is used in many different contexts. This moves an object around the screen with the mouse. The object is dropped at the location where the mouse button is released. This action is also called drag-and-drop. Clicking on an element of the interface to move it is sometimes called a grab. Click and drag

For example, you can change the position of a window by dragging on its title bar, or move a file by dragging its icon from one window and dropping it on another.

The left mouse buttons is usually used to perform drag actions, although the middle mouse button is sometimes used for an alternate drag action.

Click-and-hold

Press and do not release the left mouse button.

In most applications, you can select text with your left mouse button and paste it in another application using the middle mouse button. This is called primary selection paste, and works separately from your normal clipboard operations.

To select more than one item, you can hold the Ctrl key to select multiple items, or hold the Shift key to select a contiguous range of items. You can also drag a bounding box to select several items by starting the drag in the empty space around items and dragging out a rectangle.