Touchpad

A touchpad or trackpad is a type of pointing device. Its largest component is a tactile sensor: an electronic device with a flat surface that detects the position and motion of a user's fingers, and translates them into 2D motion to control a pointer in a graphical user interface. Touchpads are common on laptop computers, contrasted with desktop computers, with which mice are more prevalent. Trackpads are sometimes used with desktop setups where desk space is scarce. Wireless touchpads are also available as detached accessories. Due to the ability of trackpads to be made small, they were additionally used on personal digital assistants (PDAs) and some portable media players.