SINCE 1828
dictionary
thesaurus
view recents

Unionidae

plural noun
Save Word
Uni·​on·​i·​dae

Definition of Unionidae

: a very large family of freshwater mussels (suborder Submytilacea) having a pearly often roughly sculptured shell with a thick epidermis and larvae that pass through a glochidium stage and being represented in nearly all parts of the world but chiefly in North America where the nacreous shells of many of them are used for button making

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 Unionidae

New Latin, from Union-, Unio, type genus + -idae

Learn More About Unionidae

Dictionary Entries Near Unionidae

unionid

Unionidae

unionides

See More Nearby Entries 

Statistics for Unionidae

Cite this Entry

“Unionidae.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/Unionidae. Accessed 21 Jan. 2022.

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

WORD OF THE DAY

derring-do

Listen to the pronunciation of derring-do

See Definitions and Examples »

Test Your Vocabulary

Farm Idioms Quiz

  • cow coming home
  • What does 'poke' refer to in the expression 'pig in a poke'?
Name That Thing

Test your visual vocabulary with our 10-question challenge!

TAKE THE QUIZ
Universal Daily Crossword

A daily challenge for crossword fanatics.

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