Any of several marine bivalve molluscs constituting the genus Spisula (family Mactridae) (also called triangle shell); especially the large and edible S. solidissima of the west Atlantic, and S. solida of the north-east Atlantic.
Origin
Late 19th century.
Definition of surf clam in US English:
surf clam
noun
Any of several marine bivalve molluscs constituting the genus Spisula (family Mactridae) (also called triangle shell); especially the large and edible S. solidissima of the west Atlantic, and S. solida of the north-east Atlantic.