Definition of "chad"

The keypunch wasn't named after a Mr. Chadless; it was so named because, as expected, it punched tape while producing little or no chad.

2011 June 1, David P. Mikkelson, “Chad: Does the word ‘chad’ come from the Chadless keypunch, invented by a Mr. Chadless?”, in Snopes.com‎, retrieved 7 September 2016

Prior devices of the type according to the present invention have been arranged to cut out the perforations completely at a single movement, thereby producing chads or waste material which often present difficult problems of disposal.

1939 May 20, Ross A. Lake, Printing Perforating Telegraph Apparatus‎, US Patent 2255794

The small hinged discs of paper, called ‘chad’, remain attached to the body of the tape.

1959, J[ohn] W[illiam] Freebody, Telegraphy, London: Isaac Pitman & Sons

Much of the controversy seems to revolve around ballot cards designed to be perforated by a stylus but which, either through error or deliberate omission, have not been perforated with sufficient precision for a machine to count them. In some cases a piece of the card—a chad—is hanging, say by two corners. In other cases there is no separation at all, just an indentation.

2000 December 12, Supreme Court of the United States, per curiam, “Bush v. Gore”, in United States Reports, volume 531, page 98 at 105

Chad et in my meend, and zo chave still. Bet chawnt drow et out bevore tha begen'st agen, and than chell.

1839, An Exmoor Scolding, London: John Russell Smith, page 11