Home › Words › T › tridacnatridacnatridacna · noun — any member of the genus Tridacna of large saltwater clams with heavy fluted shells.Definition from Wiktionary (CC BY-SA 3.0).Among words judged in Lexicurio's Arena, tridacna ranks #2,514 of 43,221 for Qualifying.EtymologyFrom the genus name.nounAny member of the genus Tridacna of large saltwater clams with heavy fluted shells.Definitions & examples from Wiktionary (CC BY-SA 3.0).