< hardware > A card punch which cut little U-shapes in punched cards , rather than punching out a circle or rectangle. The U's made a hole when folded back.
One of the Jargon File 's correspondents believed that the term "chad" derived from the Chadless keypunch . Obviously, if the Chadless keypunch didn't make them, then the stuff that other keypunches made had to be " chad ". The assertion that the keypunch was named after its inventor is not supported by any record in US or UK patents or surname references.
(2000-11-22)