mollusk

noun

mol·​lusk ˈmä-ləsk 

variants or mollusc

: any of a large phylum (Mollusca) of invertebrate animals (such as snails, clams, or squids) with a soft unsegmented body usually enclosed in a calcareous shell

broadly : shellfish

molluscan adjective

or less commonly molluskan

mə-ˈlə-skən 

mä-

Examples of mollusk in a Sentence

Recent Examples on the Web

The discoveries span worms, mollusks, and crustaceans collected from habitats ranging from shallow waters to the ocean’s deepest trenches. —Aamir Khollam, Interesting Engineering, 16 Oct. 2025

Specifically, Larsson was searching for dentalium shells—the long, tubular shells deriving from dentaliums, a type of marine mollusk. —Christian Allaire, Vogue, 13 Oct. 2025

Paleontological excavations at this site have previously been fruitful, according to the study, with animals ranging from mollusks to iguanian lizards to dinosaur giants like titanosaurs discovered buried in the sediment. —Irene Wright, Miami Herald, 26 Sep. 2025

The mollusks have filtered most of the lakes, turning them from their old greenish hue, which allowed for only a few feet of visibility, to clear blue. —Taylor Nicioli, CNN Money, 17 Sep. 2025

Word History

Etymology

French mollusque, from New Latin Mollusca, from Latin, neuter plural of molluscus thin-shelled (of a nut), from mollis

First Known Use

1783, in the meaning defined above

Rhymes for mollusk

• mollusc

Kids Definition

mollusk

noun

mol·​lusk

variants or mollusc

ˈmäl-əsk 

: any of a large phylum of invertebrate animals (as snails, clams, and octopuses) with a soft body lacking segments and usually enclosed in a shell containing calcium

molluscan adjective

also molluskan

mə-ˈləs-kən 

mä-

Medical Definition

mollusk

noun

mol·​lusk

variants or mollusc

ˈmäl-əsk 

: any invertebrate animal of the phylum Mollusca

molluscan adjective

also molluskan

mə-ˈles-kən, mä-