cockle

From Middle English cokel, cokkel, kokkel, cocle, of uncertain origin. Perhaps a diminutive of Middle English cokke, cok (“cockle”), from Old English cocc (found in sǣcocc (“cockle”)) + -le; or perhaps from Old French coquille, from Vulgar Latin *cocchilia, from conchylia, from Ancient Greek κογχύλιον (konkhúlion), diminutive of κογχύλη (konkhúlē, “mussel”), of Pre-Greek substrate origin.

From Middle English cockil, cokil, cokylle, from Old English coccel (“darnel”), of unknown origin, perhaps from a diminutive of Latin coccus (“berry”).

Origin uncertain.

Rhyming slang, from cock and hen for ten.