tridacna gigas(n = noun.animal) giant clam - a large clam inhabiting reefs in the southern Pacific and weighing up to 500 pounds;
is a kind of clam
is a member of genus tridacna, tridacna

dacelo gigas, genus tridacna, gyromitra gigas, hydrodamalis gigas, ostrea gigas, strombus gigas, tridacna