septum

noun

(L. septum: fence, partition) (pl. septa) A membrane or wall which subdivides a cavity. In octamerous anthozoans, eight longitudinal partitions dividing gastrovascular cavity into interseptal spaces; in hexamerous forms, there are typically a multiple of six. Extends from wall of column to pharynx orally; free inner edge below pharynx bears thickening filament. Each septum bears a longitudinal muscle.
A partition separating two cavities or masses of tissue, as in fruits, as the partitions separating the locules of an ovary.