The mouse is a input device, capable of moving a virtual pointer inside a graphical interface. It can be wireless, with 1 or more buttons and can have side buttons(and some gamming versions have a lots of them).
Invented by Douglas Engelbart in 1964, the first version of this computer artifact was made of wood, and it had two metal wheels to make the horizontal and vertical input orientation.
8 years after that Bill English developed a version with the "ball mouse": A sphere inside the mouse capable of monitoring movement in any direction. The ball came into contact with two rollers that creating the pointer motion.
Today the optical mouse has completely replaced the ball mouse being supplied as standard with all new computers.