plural noun
Palae·​os·​tra·​ca | \ ˌpālēˈästrə̇kə, ˌpal- also -ˈȯs- \

Definition of Palaeostraca

in some classifications
: a class of arthropods comprising the horseshoe crabs, the eurypterids, and sometimes the trilobites — compare merostomata

Love words?

You must — there are over 200,000 words in our free online dictionary, but you are looking for one that’s only in the Merriam-Webster Unabridged Dictionary.

Start your free trial today and get unlimited access to America's largest dictionary, with:

  • More than 250,000 words that aren't in our free dictionary
  • Expanded definitions, etymologies, and usage notes
  • Advanced search features
  • Ad free!

Other Words from Palaeostraca

palaeostracan \ ¦⸗⸗¦⸗⸗kən \ adjective or noun

History and Etymology for Palaeostraca

New Latin, from pale- + -ostraca

Keep scrolling for more

Learn More about Palaeostraca

Statistics for Palaeostraca

Cite this Entry

“Palaeostraca.” Dictionary, Merriam-Webster, Accessed 20 Apr. 2021.

Style: MLA
MLACheck Mark Icon ChicagoCheck Mark Icon APACheck Mark Icon Merriam-WebsterCheck Mark Icon

Comments on Palaeostraca

What made you want to look up Palaeostraca? Please tell us where you read or heard it (including the quote, if possible).


Test Your Vocabulary

Name that Thing: Flower Edition

Name That Thing

Test your visual vocabulary with our 10-question challenge!

 AlphaBear 2

Spell words. Make bears.

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!