Venus mercenaria vs round clam

Venus mercenaria and round clam both are nouns.

Word	Noun	Adjective	Verb	Adverb
Venus mercenaria	Yes	No	No	No
round clam	Yes	No	No	No

As nouns, Venus mercenaria and round clam are synonyms defined as:

Venus mercenaria and round clam: an edible American clam; the heavy shells were used as money by some American Indians

Other synonyms of Venus mercenaria include hard-shell clam, hard clam, Mercenaria mercenaria, quahaug, quahog.

Venus mercenaria (noun)	round clam (noun)
an edible American clam; the heavy shells were used as money by some American Indians	an edible American clam; the heavy shells were used as money by some American Indians
	Atlantic coast round clams with hard shells; large clams usually used for chowders or other clam dishes