con·chos·tra·ca \-ŋˈkästrəkə also -ˈkȯs-\noun plural Usage: capitalized Etymology: New Latin, from conch- + -ostraca : a small order of freshwater crustaceans (subclass Branchiopoda) entirely enclosed in a bivalve carapace • con·chos·tra·can\-rəkən\noun-s