SEPTUM

noun one of the radial calcareous plates of a coral.

2. septum ·noun a partition that separates the cells of a fruit.

3. septum ·noun a wall separating two cavities; a partition; as, the nasal septum.

4. septum ·noun one of the transverse partitions dividing the body cavity of an annelid.

5. septum ·noun one of the transverse partitions dividing the shell of a mollusk, or of a rhizopod, into several chambers. ·see ·illust. under nautilus.