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

Share Palaeostraca

Statistics for Palaeostraca

Look-up Popularity

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).


to clear from alleged fault or guilt

Get Word of the Day daily email!

Test Your Vocabulary

Difficult Vocab Quiz

  • the-education-of-achilles-eugne-delacroix
  • Which is a synonym of discomfit?
How Strong Is Your Vocabulary?

Test your vocabulary with our 10-question quiz!

Word Winder's CrossWinder

Test Your Knowledge - and learn some interesting things along the way.


Love words? Need even more definitions?

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