trə̇ˈdaknə noun
Etymology: New Latin, from Latin, an oyster, from Greek tridaknos eaten at three bites, from tri- three + -daknos (from daknein to bite) — more at tongs
1. capitalized : a genus of marine bivalves (family Tridacnidae) having no anterior adductor muscle and an equivalve shell the valves of which are very thick and heavy and strongly plicated at the margin — see giant clam
2. -s : any mollusk of the genus Tridacna : giant clam