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 can only be applied to paper formats that are at least high. Another standard also occasionally used in the US is a "filebinder" system. Its two holes are positioned symmetrically, with the centers apart. In Sweden, a four-hole national standard is almost exclusively used. The centers of the holes are 21 mm, 70 mm and 21 mm apart. The guides help keep the paper in a straight line. The official name of this four-hole system is "triohålning", since it was adapted to the "Trio binder" which was awarded Swedish patent in 1890. The binder's inventor, Andreas Tengwall, supposedly named it