Entry 1 sense Webster, 1913 Branchiogastropoda · Bran·chi·o·gas·trop·o·da · IPA 01 n. pl. Those Gastropoda that breathe by branchiæ, including the Prosobranchiata and Opisthobranchiata. 1. Those Gastropoda that breathe by branchiæ, including the Prosobranchiata and Opisthobranchiata.(Zool.)