chad box n.
A metal box about the size of a lunchbox (or in some models a
large wastebasket), for collecting the chad (sense 2) that accumulated in Iron Age card punches. You had to open the
covers of the card punch periodically and empty the chad box. The
bit bucket was notionally the
equivalent device in the CPU enclosure, which was typically
across the room in another great gray-and-blue box.