A computer “mouse” is a hand-held input device that, when rolled across a flat surface, causes a cursor to move in a corresponding way on a display screen. A prototype mouse was part of an input console demonstrated by Douglas C. Englehart in 1968 at the Fall Joint Computer Conference in San Francisco. Popularized in 1984 by the Macintosh from Apple Computer, the mouse was the result of 15 years devoted to exploring ways to make communicating with computers simpler and more flexible.
The physical appearance of the small four-sided box with the dangling tail-like wire suggested the informal name of “mouse,” which quickly superseded the formal name. (The Handy Science Answer Book, compiled by the Science and Technology department of the Carnegie Library of Pittsburgh)