septum

septum is a   Noun

Definition:

[1] A wall separating two cavities; a partition; as, the nasal septum.

[2] A partition that separates the cells of a fruit.

[3] One of the radial calcareous plates of a coral.

[4] One of the transverse partitions dividing the shell of a mollusk, or of a rhizopod, into several chambers. See Illust. under Nautilus.

[5] One of the transverse partitions dividing the body cavity of an annelid.

Synonyms: