1783, mollusque (modern spelling from 1839), from French mollusque, from Modern Latin Mollusca (see Mollusca), the phylum name. Related: Molluscuous; molluscan.
A phylum of invertebrates with soft bodies and muscular feet. Some mollusks also have hard shells. Oysters, clams, snails, slugs, octopuses, and squid are mollusks.