[giant clam] n (ca. 1889): a very large clam (Tridacna gigas) found on the coral reefs of the Indian and Pacific oceans that sometimes weighs more than 500 pounds (227 kilograms)
GIANT CLAM
Meaning of GIANT CLAM in English
Merriam-Webster English vocab. Английский словарь Merriam Webster. 2012