plural noun

Definition of Ostracodermi

1 in some classifications : a suborder of the order Plectognathi comprising the boxfishes
2 in some classifications : an order or other category comprising the superclass Agnatha except the class Cyclostomi and some members of the class Placodermi that are known only from imperfect remains found in Ordovician, Silurian, and Devonian rocks, that lack jaws and limb girdles as well as paired fins homologous with those of recent fishes, that in most forms show the very broad anterior part of the body to be encased in a bony armor, and that have the slender scaly posterior part ending in an unsymmetrical tail

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!

History and Etymology for Ostracodermi

New Latin, from ostrac- + -dermi (from Greek derma skin)

Keep scrolling for more

Learn More About Ostracodermi

Dictionary Entries Near Ostracodermi




See More Nearby Entries 

Statistics for Ostracodermi

Cite this Entry

“Ostracodermi.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/Ostracodermi. Accessed 27 Oct. 2021.

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


Test Your Vocabulary

Dog Words Quiz

  • shiba puppy more or less demanding cuddles
  • Which of the following animals has a dog in its etymology?
Spell It

Can you spell these 10 commonly misspelled words?

Love words? Need even more definitions?

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