backbox means the rear upright section of a pinball machine, usually incorporating the score display. Lexicurio rates it Sui generis — a strength score of 90 out of 100.
Etymology
From back + box.
noun
- The rear upright section of a pinball machine, usually incorporating the score display.“The game is made exclusively in the new-type Williams cabinet design (a longer, lower styling with pedestal-mounted backbox).”