• (n. pl.) Those Gastropoda that breathe by branchiae, including the Prosobranchiata and Opisthobranchiata.
Bran`chi·o·gas·trop'o·da noun plural [ New Latin , from Greek ... gill + English gastropoda .] (Zoology) Those Gastropoda that breathe by branchiæ, including the Prosobranchiata and Opisthobranchiata.