Northern lobster vs American lobster

Northern lobster and American lobster both are nouns.

Word	Noun	Adjective	Verb	Adverb
Northern lobster	Yes	No	No	No
American lobster	Yes	No	No	No

As nouns, Northern lobster and American lobster are synonyms defined as:

Northern lobster and American lobster: lobster of Atlantic coast of America

Other synonyms of Northern lobster include Homarus americanus, Maine lobster.

As nouns, Northern lobster and American lobster are synonyms defined as:

Northern lobster and American lobster: flesh of cold-water lobsters having large tender claws; caught from Maine to the Carolinas

Other synonyms of Northern lobster include Maine lobster.

Northern lobster (noun)	American lobster (noun)
lobster of Atlantic coast of America	lobster of Atlantic coast of America
flesh of cold-water lobsters having large tender claws; caught from Maine to the Carolinas	flesh of cold-water lobsters having large tender claws; caught from Maine to the Carolinas