Merriam-Webster Logo
SINCE 1828
Menu
dictionary thesaurus

peridinium

noun
peri·​din·​i·​um | \ ˌperəˈdinēəm\

Definition of peridinium

1 capitalized : the type genus of Peridiniidae comprising marine and freshwater dinoflagellates that are typically subspherical to ovoid in outline and that sometimes have the test prolonged into short horns — compare ceratium
2 plural peridiniums\ -​ēəmz\ or peridinia\ -​ēə\ : any flagellate of the genus Peridinium

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 peridinium

borrowed from New Latin, borrowed from Greek peridīn-, base of peridīneîn “to whirl, spin around” (from peri- peri- + dīneîn “to whirl, spin about”) + New Latin -ium -ium

Keep scrolling for more

Learn More about peridinium

Statistics for peridinium

Look-up Popularity

Comments on peridinium

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

Show Comments  Hide Comments 

WORD OF THE DAY

auxiliary

Listen to the pronounciation of auxiliary

providing supplementary assistance

Get Word of the Day daily email!

Test Your Vocabulary

Farm Idioms Quiz

  • cow coming home
  • What does 'poke' refer to in the expression 'pig in a poke'?
How Strong Is Your Vocabulary?

Test your vocabulary with our 10-question quiz!

TAKE THE QUIZ
SCRABBLE® Sprint

Test Your Knowledge - and learn some interesting things along the way.

TAKE THE QUIZ
Love words? Need even more definitions?

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

Words at Play
Ask the Editors
Word Games