/chad/ 1. The perforated edge strips on printer paper, after they have been separated from the printed portion. Also called selvage and perf.
2. (Obsolete) The confetti-like paper bits punched out of cards or paper tape and which collected in the chad box. This was also called "chaff", "computer confetti" and "keypunch droppings".
Historical note: One correspondent believes "chad" derives from the Chadless keypunch (named after its inventor), which cut little U-shapes in the card, rather than punching out a circle or rectangle. The U's made a hole when folded back. It was clear that if the Chadless keypunch didn't make them, then the stuff that other keypunches made had to be "chad".