Opisthobranchia

plural noun

Opis·​tho·​bran·​chia

zoology

: a large order of Euthyneura comprising marine gastropod mollusks having the gills when present posterior to the heart and having no operculum compare streptoneura see nudibranchia, tectibranchia

opisthobranchiate

⸗¦⸗⸗¦braŋkēə̇t

-ēˌāt

adjective or noun

Word History

Etymology

New Latin, from opisth- + -branchia

The Ultimate Dictionary Awaits

Expand your vocabulary and dive deeper into language with Merriam-Webster Unabridged.

1. Expanded definitions
2. Detailed etymologies
3. Advanced search tools
4. All ad-free

Discover what makes Merriam-Webster Unabridged the essential choice for true word lovers.

Start Your Free Trial Now