ac·​tin·​o·​stome | \ ak-ˈti-nə-ˌstōm\
plural -s

Definition of actinostome

1 : the mouth of a radially symmetrical animal
2 : the peristome of an echinoderm

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 actinostome

1860, in the meaning defined at sense 1

History and Etymology for actinostome

actin- + -stome

Keep scrolling for more

Learn More about actinostome

Statistics for actinostome

Look-up Popularity

Time Traveler for actinostome

The first known use of actinostome was in 1860

See more words from the same year

Comments on actinostome

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


to move or proceed with twists and turns

Get Word of the Day daily email!

Test Your Vocabulary

Words from Greek and Latin Quiz

  • roman forum
  • Which of the following months comes from a Latin word for “ten”?
How Strong Is Your Vocabulary?

Test your vocabulary with our 10-question quiz!

Bee Cubed

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!