marine mussel: marine bivalve mollusk having a dark elongated shell; live attached to solid objects especially in intertidal zones
mussel: marine or freshwater bivalve mollusk that lives attached to rocks etc.
leninism: the political and economic theories of Lenin which provided the guiding doctrine of the Soviet Union; the modification of Marxism by Lenin stressed that imperialism is the highest form of capitalism (which shifts the struggle from developed to underdeveloped countries)