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.
Join MWU now and get access to America’s largest dictionary, with:
- 300,000 words that aren't in our free dictionary
- Expanded definitions, etymologies, and usage notes
- Advanced search features
- Ad free!
Origin and Etymology of unionidae
New Latin, from Union-, Unio, type genus + -idae
Seen and Heard
What made you want to look up Unionidae? Please tell us where you read or heard it (including the quote, if possible).