Inside the Universes

Words with a similar base: trackball

'trackball'

[trackball.n.01] as in: an electronic device consisting of a rotatable ball in a housing; used to position the cursor and move images on a computer screen

Examples:
a trackball is essentially an upside-down mouse

Origins

					trackball (English)
├── ball (English)
│   └── bal (Middle English (1100-1500))
└── track (English)