Main Entry: opis·tho·branch

Pronunciation: \ə-ˈpis-thə-ˌbraŋk\

Function: noun

Inflected Form(s): plural opis·tho·branchs

Etymology: New Latin Opisthobranchia, from Greek opisthen behind (akin to Greek epi on) + branchia gills — more at epi-

Date: circa 1856

: any of a subclass (Opisthobranchia) of marine gastropod mollusks that have the gills when present posterior to the heart and often lack a shell

— opisthobranch adjective