The pointing device (generally referred to as the mouse). When referring to laptops, please specify if it is the trackpad and not an external mouse by using the trackpad tag. Only use for hardware issues.
Mouse can refer to a variety of similar pointing devices that drive and control the cursor. Most of the mouse have 2 to 3 buttons, but some can have "side buttons" or extra buttons. The mouse movement in the screen is represented by the pointer which is usually a white arrow.
In Linux systems the pointer movement is controlled by the X Window System, which is Xorg. All input devices signals follow the following process:
+-----------+ +-------------+ +-----+
| Mouse |------------->| motherboard |-------->| CPU |
+-----------+ +-------------+ +-----+
USB, PS/2, … PCI, …
click down/up
+--------+ +----------+ +-------------+
-------->| kernel |------->| X server |--------->| application |
+--------+ +----------+ +-------------+
interrupt scancode keysym
=keycode +modifiers
As can be seen, the Mouse signals are transmitted to the motherboard, from there they issue CPU interrupts which are catch by the kernel. This scans the code and the X server reads it. Depending the action the application reacts.
Tag recommendation
If you want to modify the behavior of your mouse clicks and speed, you are most likely using the xorg when using Xorg, or xserver when using other X window system.
When using touchpads, use the touchpad instead. For how the pointer behaves with the windows, use window-manager if you want something general, unity for unity.
Recommended read
Further reading:
