mol·lusk [ mólləsk ](pluralmol·lusks) or mol·lusc [ mólləsk ](pluralmol·luscs)
noun
Definition:
clam, snail, slug, or octopus: an invertebrate with a soft unsegmented body, usually protected by a shell in one, two, or three pieces, e.g. the snails and the octopus. Most mollusks live in or near water. Phylum Mollusca.
[Late 18th century. < French mollusque< Latin molluscus "thin-shelled nut" < mollis "soft"]