Type genus of the family Tridacnidae giant clams

Wiktionary Word definitions in Wiktionary
n. Any member of the genus (taxlink Tridacna genus noshow=1) of large saltwater clams with heavy fluted shells.

Wikipedia Word definitions in Wikipedia
Tridacna is a genus of large saltwater clams , marine bivalve mollusks in the subfamily Tridacninae , the giant clams. They have heavy shells, fluted with 4 to 6 folds. The mantle is brightly coloured. They inhabit shallow waters of coral reefs in warm ...

The Collaborative International Dictionary Word definitions in The Collaborative International Dictionary
Tridacna \Tri*dac"na\, n. [L., pl., a kind of oysters, fr. Gr. ? eaten at three bites, ? tri- + ? to bite.] (Zo["o]l.) A genus of very large marine bivalve shells found on the coral reefs of the Indian and Pacific Oceans. One species ( Tridacna gigas ) ...