cherrystone clam vs hard clam

cherrystone clam and hard clam both are nouns.

Word	Noun	Adjective	Verb	Adverb
cherrystone clam	Yes	No	No	No
hard clam	Yes	No	No	No

As nouns, hard clam is a hypernym of cherrystone clam; that is, hard clam is a word with a broader meaning than cherrystone clam:

cherrystone clam: a half-grown quahog
hard clam: an edible American clam; the heavy shells were used as money by some American Indians

Other hypernyms of cherrystone clam include hard-shell clam, Mercenaria mercenaria, quahaug, quahog, round clam, Venus mercenaria.

cherrystone clam (noun)	hard clam (noun)
a half-grown quahog	an edible American clam; the heavy shells were used as money by some American Indians
small quahog larger than a littleneck; eaten raw or cooked as in e.g. clams casino