septum

Etymology

Borrowed from Latin sēptum (“enclosure, wall, fence”).

noun

1. (biology) A wall separating two cavities; a partition.
   1. (anatomy) Ellipsis of nasal septum.: the cartilaginous center wall of the nose separating the two nostrils.
      Deviated septum, a shift from the midline that commonly occurs in normal growth, is present in most adults. 2002, Springhouse, Illustrated Manual of Nursing Practice, Lippincott Williams & Wilkins, page 1158
      Sally got a dagger hung from her septum O'Malley cut his ears off, but wishes that he kept 'em 2008, Neil Cicierega (lyrics and music), “Modify”, in View-Monster, performed by Lemon Demon
   2. (anatomy) Either of the two walls that separate the atria or ventricles of the heart into left and right chambers.
   3. (botany) A partition that separates the cells of a fruit.
   4. (mycology) A partition that separates the cells of a (septated) fungus.
   5. (zoology) One of the radial calcareous plates of a coral.
   6. (zoology) One of the transverse partitions dividing the shell of a mollusk, or of a rhizopod, into several chambers.
   7. (zoology) One of the transverse partitions dividing the body cavity of an annelid.
2. (colloquial) Ellipsis of septum ring. or septum piercing.
   Look, I got a new septum!