Trackball vs. Trackpad — What's the Difference?

A trackball is a pointing device consisting of a ball held by a socket containing sensors to detect a rotation of the ball about two axes—like an upside-down mouse with an exposed protruding ball. Users roll the ball to position the on-screen pointer, using their thumb, fingers, or commonly the palm of the hand while using the fingertips to press the mouse buttons.

Touchpad

A ball mounted in a stationary housing and rotated to control a pointer on a computer screen.

(computing) A pointing device consisting of a ball housed in a socket

An electronic device consisting of a rotatable ball in a housing; used to position the cursor and move images on a computer screen;