A piece of punch-through paper on a voting ballot that has not fully detached from the card-stock.(noun)
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Use "hanging chad" in a sentence
"Seelye in the New York Times: “Variants include dimpled chad (bulging but not pierced), pregnant chad (attached by all four corners to a ballot that is either bulging or pierced), hanging chad (attached by a single corner), swinging-door chad (attached by two corners) and tri chad (attached by three corners).”"