cockle (n.1)

type of mollusk, early 14c., from Old French coquille (13c.) "scallop, scallop shell; mother of pearl; a kind of hat," altered (by influence of coque "shell") from Vulgar Latin *conchilia, from Latin conchylium "mussel, shellfish," from Greek konkhylion "little shellfish," from konkhe "mussel, conch." Phrase cockles of the heart (1660s) is perhaps from similar shape, or from Latin corculum, diminutive of cor "heart."

cockle (n.2)

flowering weed that grows in wheat fields, Old English coccel "darnel," used in Middle English to translate the Bible word now usually given as tares (see tare (n.1)). It is in no other Germanic language and may be from a diminutive of Latin coccus "grain, berry."