bivalve vs cockle

bivalve and cockle both are nouns.

Word	Noun	Adjective	Verb	Adverb
bivalve	Yes	Yes	No	No
cockle	Yes	No	Yes	No

As nouns, cockle is a hyponym of bivalve; that is, cockle is a word with a more specific, narrower meaning than bivalve:

bivalve: marine or freshwater mollusks having a soft body with platelike gills enclosed within two shells hinged together
cockle: common edible, burrowing European bivalve mollusk that has a strong, rounded shell with radiating ribs

Other hyponyms of bivalve include clam, oyster, ark shell, blood clam, mussel, escallop, scallop, scollop, piddock.

bivalve (noun)	cockle (noun)
marine or freshwater mollusks having a soft body with platelike gills enclosed within two shells hinged together	common edible, burrowing European bivalve mollusk that has a strong, rounded shell with radiating ribs
	common edible European bivalve

bivalve (adjective)	cockle (adjective)
used of mollusks having two shells (as clams etc.)

bivalve (verb)	cockle (verb)
	to gather something into small wrinkles or folds
	stir up (water) so as to form ripples