"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 M.E. 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" (1326). The theory is that this was originally done to salmon, hence the name.