In computing, a mouse (plural mouses, mice, or mouse devices) is a pointing device that functions by detecting two-dimensional motion relative to its supporting surface. Physically, a mouse consists of an object held under one of the user's hands, with one or more buttons. It sometimes features other elements, such as "wheels", which allow the user to perform various system-dependent operations, or extra buttons or features can add more control or dimensional input. The mouse's motion typically translates into the motion of a pointer on a display, which allows for fine control of a Graphical User Interface.
The name mouse, originated at the Stanford Research Institute, derives from the resemblance of early models (which had a cord attached to the rear part of the device, suggesting the idea of a tail) to the common mouse.
The first marketed integrated mouse – shipped as a part of a computer and intended for personal computer navigation – came with the Xerox 8010 Star Information System in 1981. However, the mouse remained relatively obscure until the appearance of the Apple Macintosh; in 1984 a prominent PC columnist commented the release of this new computer with a mouse: “There is no evidence that people want to use these things.”
A mouse now comes with most computers and many other varieties can be bought separately.

Etymology and plural
The first known publication of the term "mouse" as a pointing device is in Bill English's 1965 publication "Computer-Aided Display Control".
The Compact Oxford English Dictionary (third edition) and the fourth edition of The American Heritage Dictionary of the English Language endorse both computer mice and computer mouses as correct plural forms for computer mouse. Some authors of technical documents may prefer either mouse devices or the more generic pointing devices. The plural mouses treats mouse as a "headless noun."
Two manuals of style in the computer industry – Sun Technical Publication's Read Me First: A Style Guide for the Computer Industry and Microsoft Manual of Style for Technical Publications from Microsoft Press – recommend that technical writers use the term mouse devices instead of the alternatives.

Mechanical mouse devices
Bill English, builder of Engelbart's original mouse, invented the ball mouse in 1972 while working for Xerox PARC. The ball-mouse replaced the external wheels with a single ball that could rotate in any direction. It came as part of the hardware package of the Xerox Alto computer. Perpendicular chopper wheels housed inside the mouse's body chopped beams of light on the way to light sensors, thus detecting in their turn the motion of the ball. This variant of the mouse resembled an inverted trackball and became the predominant form used with personal computers throughout the 1980s and 1990s. The Xerox PARC group also settled on the modern technique of using both hands to type on a full-size keyboard and grabbing the mouse when required.
The ball mouse utilizes two rollers rolling against two sides of the ball. One roller detects the forward–backward motion of the mouse and other the left–right motion. The motion of these two rollers causes two disc-like encoder wheels to rotate, interrupting optical beams to generate electrical signals. The mouse sends these signals to the computer system by means of connecting wires. The driver software in the system converts the signals into motion of the mouse pointer along X and Y axes on the screen.
Ball mice and wheel mice were manufactured for Xerox by Jack Hawley, doing business as The Mouse House in Berkeley, California, starting in 1975.
Based on another invention by Jack Hawley, proprietor of the Mouse House, Honeywell produced another type of mechanical mouse. Instead of a ball, it had two wheels rotating at off axes. Keytronic later produced a similar product.
Modern computer mice took form at the École polytechnique fédérale de Lausanne (EPFL) under the inspiration of Professor Jean-Daniel Nicoud and at the hands of engineer and watchmaker André Guignard. This new design incorporated a single hard rubber mouseball and three buttons, and remained a common design until the mainstream adoption of the scroll-wheel mouse during the 1990s.
Another type of mechanical mouse, the "analog mouse" (now generally regarded as obsolete), uses potentiometers rather than encoder wheels, and is typically designed to be plug-compatible with an analog joystick. The "Color Mouse," originally marketed by Radio Shack for their Color Computer (but also usable on MS-DOS machines equipped with analog joystick ports, provided the software accepted joystick input) was the best-known example.

Mechanical or opto-mechanical
A mouse described as simply "mechanical" has a contact-based incremental rotary encoder,[citation needed] a system prone to drag and unreliability of contact. Opto-mechanical mice still use a ball or crossed wheels, but detect shaft rotation using an optical encoder with lower friction and more certain performance.

Optical mice
An optical mouse uses a light-emitting diode and photodiodes to detect movement relative to the underlying surface, rather than moving some of its parts – as in a mechanical mouse.