- mussel - black marine bivalves usually steamed in wine
--1 is a kind of shellfish
--1 is a part of edible mussel, Mytilus edulis- mussel - marine or freshwater bivalve mollusk that lives attached to rocks etc.
--2 is a kind of bivalve, pelecypod, lamellibranch
--2 has particulars: marine mussel, mytilid; freshwater mussel, freshwater clam - mussel - marine or freshwater bivalve mollusk that lives attached to rocks etc.