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periostracum

American

[per-ee-os-truh-kuhm] / ˌpɛr iˈɒs trə kəm /

noun

the external, chitinlike covering of the shell of certain mollusks that protects the limy portion from acids.

Other Word Forms

Derived Forms

periostracal

adjective

Inflected Forms

Nouns

periostraca

plural

Etymology

Origin of periostracum

1830–40; < New Latin, equivalent to peri- peri- + ostracum a shell < Greek óstrakon. See oyster

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.