trackball

Definitions

General English

Computing

  • noun a device used to move a cursor on-screen which is controlled by turning a ball contained in a case

Electronics

  • A pointing device which incorporates a ball which is rotated by a hand or by fingers upon its stationary base. The movements of the ball translate into cursor movements on the display screen, and one or more buttons serve for selecting, performing functions, or the like.
http://www.dictionarycentral.com/definition/trackball.html