A mouse is a handheld pointing device for computers, being a small object fitted with one or more buttons and shaped to sit naturally under the hand. The underside of the mouse houses a device that detects the mouse's motion relative to the flat surface on which it moves. The mouse's 2D motion is typically translated into the motion of a pointer on the display.
It is called a mouse primarily because the cord on early models resembled the rodent's tail, and also because the motion of the pointer on the screen can be mouse-like.
In popular usage, the plural can be either mice or mouses.
