from
The Collaborative International Dictionary of English v.0.48
Septum \Sep"tum\, n.; pl. {Septa}. [L. septum, saeptum, an
inclosure, hedge, fence, fr. sepire, saepire, to hedge in,
inclose.]
1. A wall separating two cavities; a partition; as, the nasal
septum.
[1913 Webster]
2. (Bot.) A partition that separates the cells of a fruit.
[1913 Webster]
3. (Zool.)
(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.
[1913 Webster]