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Old English cypera "male salmon," perhaps related to coper "reddish-brown metal" (see copper), on resemblance of color. Another theory connects it to kip, name for the sharp, hooked lower jaw of the male salmon in breeding season, from Middle English kippen "to snatch, tug, pull." The modern word usually refers to kippered herring, from a verb meaning "to cure a fish by cleaning, salting, and spicing it" (early 14c.). The theory is that this originally was done to salmon, hence the name.