ac·​tin·​o·​branch | \ ak-ˈti-nə-ˌbraŋk\
variants: or actinobranchia \ ¦ak-​tə-​(ˌ)nō-​ˈbraŋ-​kē-​ə \
plural -s

Definition of actinobranch

: a gill-like organ of certain Anthozoa

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 actinobranch

circa 1901, in the meaning defined above

History and Etymology for actinobranch

New Latin actinobranchia, from actin- + branchia

Keep scrolling for more

Learn More about actinobranch

Statistics for actinobranch

Look-up Popularity

Time Traveler for actinobranch

The first known use of actinobranch was circa 1901

See more words from the same year

Comments on actinobranch

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


miscellaneous remnants or debris

Get Word of the Day daily email!

Test Your Vocabulary

The Exceptions Quiz III

  • one green toy robot amidst many red toy robots
  • Which of these words does not mean "nonsense"?
True or False

Test your knowledge - and maybe learn something along the way.

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!