plural noun
Ag·​na·​tha | \ ˈag-nə-thə \

Definition of Agnatha

1 : a superclass or other division of Vertebrata comprising those without jaws — compare gnathostomata
2 : a group of carnivorous air-breathing snails without jaws

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!

First Known Use of Agnatha

1865, in the meaning defined at sense 1

History and Etymology for Agnatha

borrowed from New Latin, from a- a- entry 2 + -gnatha -gnatha

Keep scrolling for more

Learn More About Agnatha

Time Traveler for Agnatha

Time Traveler

The first known use of Agnatha was in 1865

See more words from the same year

Statistics for Agnatha

Cite this Entry

“Agnatha.” Dictionary, Merriam-Webster, Accessed 20 Jun. 2021.

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


Test Your Vocabulary

Return of Name that Color!

  • a light greenish blue color
  • Name that color:
How Strong Is Your Vocabulary?

Test your vocabulary with our 10-question quiz!


Anagram puzzles meet word search.

Love words? Need even more definitions?

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