cod vs Atlantic cod

cod and Atlantic cod both are nouns.

Word	Noun	Adjective	Verb	Adverb
cod	Yes	Yes	Yes	No
Atlantic cod	Yes	No	No	No

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

cod (noun)	Atlantic cod (noun)
major food fish of Arctic and cold-temperate waters	one of the world's most important commercial fishes
lean white flesh of important North Atlantic food fish; usually baked or poached
the vessel that contains the seeds of a plant (not the seeds themselves)

cod (adjective)	Atlantic cod (adjective)
payable by the recipient on delivery

cod (verb)	Atlantic cod (verb)
harass with persistent criticism or carping
fool or hoax