Pronunciation: (rad'i-kul), [key]
a. the lower part of the axis of an embryo; the primary root. See diag. under plumule.
b. a rudimentary root; radicel or rootlet.
2. Chem.(formerly) radical (def. 12).
3. Anat.a small rootlike part or structure, as the beginning of a nerve or vein.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.