Pronunciation: (rā'kis), [key]
—pl. ra•chis•es, rach•i•desPronunciation: (rak'i-dēz", rā'ki-). [key]
a. the axis of an inflorescence when somewhat elongated, as in a raceme.
b. (in a pinnately compound leaf or frond) the prolongation of the petiole along which the leaflets are disposed.
c. any of various axial structures.
2. Ornith.the part of the shaft of a feather bearing the web. See illus. under feather.
3. Anat.See spinal column. Also,rhachis.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.