edible mollusk, 1580s, shortening of periwinkle (n.2).
Entries linking to winkle
periwinkle n.2
kind of sea snail, 1520s, apparently an alteration of Old English pinewincle (probably by influence of Middle English parvink; see periwinkle (n.1)); from Old English pine-, which probably is from Latin pina "mussel," from Greek pine. The second element is wincel "corner; spiral shell," from Proto-Germanic *winkil-, from PIE root *weng- "to bend, curve" (see wink (v.)). But no Middle English forms have been found.