what is a shellfish
Shellfish, any aquatic invertebrate animal having a shell and belonging to the phylum Mollusca, the class Crustacea (phylum Arthropoda), or the phylum Echinodermata. The term is often used for the edible species of the groups, especially those that are fished or raised commercially. Bivalve mollusks, including oysters, mussels, scallops, and clams, rank among the most commercially important shellfish throughout the world. Certain gastropod mollusks, such as abalone, whelk, and conch, are also marketed.
n. pl. shellfish or shellÂ·fishÂ·es. 1. 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. 2. An edible mollusk, in contrast to a crustacean: regulations concerning fish, crustaceans, and shellfish. 3. The edible flesh of such animals.