Entry 1 sense Webster, 1913 Inferobranchiata · In·fe·ro·bran·chi·a·ta · IPA 01 n. pl. A suborder of marine gastropod mollusks, in which the gills are between the foot and the mantle. 1. A suborder of marine gastropod mollusks, in which the gills are between the foot and the mantle.(Zool.)