[per-ee-os-truh-kuh m]

noun, plural per·i·os·tra·ca [per-ee-os-truh-kuh] /ˌpɛr iˈɒs trə kə/.

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

Nearby words

  1. periosteoplastic amputation,
  2. periosteosis,
  3. periosteotomy,
  4. periosteum,
  5. periostitis,
  6. periotic,
  7. periovaritis,
  8. peripachymeningitis,
  9. peripancreatitis,
  10. peripatetic

Origin of periostracum

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

Related formsper·i·os·tra·cal, adjective Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for periostracum

  • 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