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
Hole punch with ISO 838 are the norm. In the US, the three-hole punch is most common. Less frequently seen is the two-hole filebinder punch. In Japan, loose leaf in A4 and JIS B5 sizes (for binders) usually has 30 and 26 holes respectively according to the standard JIS Z 8303 (section 11); which specifies holes of 6±0.5mm of diameter, with their centers every 9.5±1mm, and a distance of 6.5±0.5mm from the center of the holes to the edge of the paper with the additional restriction that the holes must be placed in positions symmetric to the axis across the middle of