Of, pertaining to, or resembling a rostrum.In zoology: Of or pertaining to a rostrum in any sense; rostellar; rostriform.Having a rostrum or beak of this or that kind; rostrate: usually in composition with a qualifying epithet: as, lamellirostral, longirostral, fissirostral, conirostral, cultrirostral, curvirostral, rectirostral, dentirostral, recurvirostral, pressirostral, tenuirostral, serratirostral, etc. See the compounds.n. A scale covering the end of the nose in reptiles; the rostral shield.