noun.
Any of various edible aquatic invertebrate animals having a shell, especially mollusks such as clams and oysters, and crustaceans such as lobsters, crabs, and shrimp.
noun.
An edible mollusk, in contrast to a crustacean.
noun.
The edible flesh of such animals.
The Century Dictionary and Cyclopedia
noun.
An aquatic animal, not a fish, having a shell, and especially one which comes under popular notice as used for food or for ornament.
noun.
A crustaceous animal, or crustacean, as a crab, lobster, shrimp, or prawn.
the GNU version of the Collaborative International Dictionary of English
noun.
Any aquatic animal whose external covering consists of a shell, either testaceous, as in oysters, clams, and other mollusks, or crustaceous, as in lobsters and crabs.