Hanging chad

Chad refers to fragments sometimes created when holes are made in a paper, card or similar synthetic materials, such as computer punched tape or punched cards. "Chad" has been used both as a mass noun (as in "a pile of chad") and as a countable noun (pluralizing as in "many chads").

In the 2000 United States presidential election, many Florida votes used Votomatic-style punched card ballots where incompletely punched holes resulted in partially punched chads: either a "hanging chad", where one or more corners were still attached, or a "fat chad" or "pregnant chad", where all corners were still attached, but an indentation appears to have been made. These votes were not counted by the tabulating machines. The aftermath of the controversy caused the rapid discontinuance of punch card ballots in the United States.

Chad is sometimes used as confetti.

The origin of the term chad is uncertain. Patent documents from the 1930s and 1940s show the word "chad", often in reference to punched tape used in telegraphy. These patents sometimes include synonyms such as "chaff" and "chips". A patent filing in 1930 included a "receptacle or chad box ... to receive the chips cut from the edge of the tape." A 1938 patent filing included a "chaff or chad chute" to collect the waste fragments. Both patents were assigned to Teletype Corporation.

The plural chads is attested from about 1939, along with chadless, meaning "without [loose] chad". Clear definitions for both terms are offered by Walter Bacon in a patent application filed in 1940 assigned to Bell Telephone Laboratories: "... In making these perforations, the perforator cuts small round pieces of paper, known in the art as chads, out of the tape. These chads are objectionable ... Chadless tape is prepared by feeding blank tape through a 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."

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