Rad"ish (rd"sh), n. [F. radis; cf. It. radice, Pr. raditz; all fr. L.
radix, -icis, a root, an edible root, especially a radish, akin to E.
wort. See Wort, and cf. Eradicate, Race a root, Radix.] (Bot.) The
pungent fleshy root of a well-known cruciferous plant (Raphanus
sativus); also, the whole plant.
Radish fly (Zoöl.), a small two- winged fly (Anthomyia raphani) whose
larvæ burrow in radishes. It resembles the onion fly. -- Rat-tailed
radish (Bot.), an herb (Raphanus caudatus) having a long, slender pod,
which is sometimes eaten. -- Wild radish (Bot.), the jointed charlock.
Ra"di*us (r"d*s), n.; pl. L. Radii (- ); E. Radiuses (-s*z). [L., a
staff, rod, spoke of a wheel, radius, ray. See Ray a divergent line.]
1. (Geom.) A right line drawn or extending from the center of a circle
to the periphery; the semidiameter of a circle or sphere.
2. (Anat.) The preaxial bone of the forearm, or brachium, corresponding
to the tibia of the hind limb. See Illust. of Artiodactyla.
The radius is on the same side of the limb as the thumb, or pollex, and
in man it is so articulated that its lower end is capable of partial
rotation about the ulna.
3. (Bot.) A ray, or outer floret, of the capitulum of such plants as
the sunflower and the daisy. See Ray, 2.
4. pl. (Zoöl.) (a) The barbs of a perfect feather. (b) Radiating
organs, or color-markings, of the radiates.