Chad (paper) device which will not punch a complete circle in the tape but, instead, will only cut approximately three-quarters of the circumference of a circle ... thereby leaving a movable, or hinged, lid of paper in the tape." In the "New Hacker's Dictionary", two unattributed and likely humorous derivations for "chad" are offered, a back-formation from a personal name "Chadless" and an acronym for "Card Hole Aggregate Debris". Other etymologies claim derivation from the Scottish name for river gravel, "chad", or the British slang for louse, "chat". When a chad is not fully detached, it is described by various terms corresponding
Edge-notched card used a system of small edge-notched cards in paper pockets in the back of library books to keep track of them. Edge-notched cards were also used for course scheduling in some high schools and colleges during the same era. Needle cards (another term for edge-notched cards) are index cards with text, written by hand or typewriter, that have a line of prepunched holes along one or more sides. By cutting or punching away (notching out) the paper between a hole and the edge of the card, the card is associated with a category. By putting long knitting needles through certain