shellfish

nouns

meat of edible aquatic invertebrate with a shell (especially a mollusk or crustacean)
shellfish
is a part of
invertebrate having a soft unsegmented body usually enclosed in a shell
mollusc, mollusk, shellfish
is a type of (narrower)
edible fish (broadly including freshwater fish) or shellfish or roe etc
seafood
invertebrate having a soft unsegmented body usually enclosed in a shell
mollusc, mollusk, shellfish