Any one of the large bivalve mollusks found on the open seacoast, especially those of the family Mactridae, as the common American species. (Mactra, / Spisula, solidissima); -- called also beach clam, and surf clam.
SEA CLAM
Meaning of SEA CLAM in English
Webster's Revised Unabridged English Dictionary. Пересмотренный полный словарь английского языка Webster. 2012