mol·lusk also mol·lusc (mŏləsk)
Any of numerous chiefly marine invertebrates of the phylum Mollusca, typically having a soft unsegmented body, a mantle, and a protective calcareous shell, and including the snails, clams, and squids.
[French mollusque, from New Latin Mollusca, phylum name, from neuter pl. of Latin molluscus, thin-shelled, from mollis, soft; see mel-1 in the Appendix of Indo-European roots.]
mol·luscous (mə-lŭskəs) adj.
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2018 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.