ag·na·than | \ ˈag-nə-thən \
plural agnathans

Definition of agnathan 

: jawless fish Two jawless fishes (agnathans) are recognized in these fossils … based on differences in the shape and histology of their tubercles … —Moya Meredith Smith, Science, 18 Jan. 1991

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 agnathan

1939, in the meaning defined above

History and Etymology for agnathan

agnatha + -an entry 1

Keep scrolling for more

Learn More about agnathan

Statistics for agnathan

Look-up Popularity

Time Traveler for agnathan

The first known use of agnathan was in 1939

See more words from the same year

Comments on agnathan

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


by word of mouth

Get Word of the Day daily email!

Test Your Vocabulary

Name that Food Quiz

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!