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