calamus

1. 1. See sweet flag.
   2. The aromatic underground stem of the sweet flag, yielding an oil used in perfumery.
2. Any of various chiefly tropical Asian climbing palms of the genus Calamus, having strong flexible stems used as a source of rattan.
3. See quill (sense 1).

[Latin, reed, from Greek kalamos.]

In the shape of a reed or pen.

• c. scriptorius — reed-shaped portion of the floor of the fourth ventricle of the brain situated between the restiform bodies.

The noun has 4 meanings:

Meaning #1: any tropical Asian palm of the genus Calamus; light tough stems are a source of rattan canes

Meaning #2: the aromatic root of the sweet flag used medicinally

Meaning #3: perennial marsh plant having swordlike leaves and aromatic roots
  Synonyms: sweet flag, sweet calamus, myrtle flag, flagroot, Acorus calamus

Meaning #4: the hollow shaft of a feather
  Synonyms: quill, shaft