RHACHIDES

Noun

rhachides

plural of rhachis

Source: Wiktionary

RHACHIS

Rha"chis, n.; pl. E. Rhachises, L. Rhachides. Etym: [See Rachis.] [Written also rechis.]

1. (Anat.)

Definition: The spine.

2. (Bot.) (a) The continued stem or midrib of a pinnately compound leaf, as in a rose leaf or a fern. (b) The principal axis in a raceme, spike, panicle, or corymb.

3. (Zoöl.) (a) The shaft of a feather. The rhachis of the after-shaft, or plumule, is called the hyporhachis. (b) The central cord in the stem of a crinoid. (c) The median part of the radula of a mollusk. (d) A central cord of the ovary of nematodes.

Source: Webster’s Unabridged Dictionary 1913 Edition