RHACHIS

noun the spine.

2. rhachis ·noun a central cord of the ovary of nematodes.

3. rhachis ·noun the central cord in the stem of a crinoid.

4. rhachis ·noun the median part of the radula of a mollusk.

5. rhachis ·noun the principal axis in a raceme, spike, panicle, or corymb.

6. rhachis ·noun the continued stem or midrib of a pinnately compound leaf, as in a rose leaf or a fern.

7. rhachis ·noun the shaft of a feather. the rhachis of the after-shaft, or plumule, is called the hyporhachis.