SEPTUM

‖Sep″tum (?), n.; pl. Septa (#). [[L. septum, saeptum, an inclosure, hedge, fence, fr. sepire, saepire, to hedge in, inclose.]] 1. 1. A wall separating two cavities; a partition; as, the nasal septum.
2. 2. (Bot.) A partition that separates the cells of a fruit.
3. 3. (Zoöl.) (a) One of the radial calcareous plates of a coral. (b) One of the transverse partitions dividing the shell of a mollusk, or of a rhizopod, into several chambers. See Illust. under Nautilus. (c) One of the transverse partitions dividing the body cavity of an annelid.