[ per-ee-os-truh-kuhm ]

noun,plural per·i·os·tra·ca [per-ee-os-truh-kuh]. /ˌpɛr iˈɒs trə kə/.
  1. the external, chitinlike covering of the shell of certain mollusks that protects the limy portion from acids.

Origin of periostracum

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

Other words from periostracum

  • per·i·os·tra·cal, adjective

Words Nearby periostracum Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use periostracum in a sentence

  • Gray calls it the periostracum, from the membranous skin covering the bones of quadrupeds.

    A Conchological Manual | George Brettingham Sowerby
  • The periostracum, or epidermis, is heavy and often velvety or even hairy.

    The Sea-beach at Ebb-tide | Augusta Foote Arnold