Rha"chis (?), n.; pl. E. Rhachises (#), L. Rhachides (#). [See Rachis.] [Written also rechis.]
2. Bot. (a)
The continued stem or midrib of a pinnately compound leaf, as in a rose leaf or a fern.
The principal axis in a raceme, spike, panicle, or corymb.
3. Zool. (a)
The shaft of a feather. The rhachis of the after-shaft, or plumule, is called the hyporhachis.
The central cord in the stem of a crinoid.
The median part of the radula of a mollusk.
A central cord of the ovary of nematodes.
© Webster 1913.