Webster 1913 Edition
[L., a staff, rod, spoke of a wheel, radius, ray. See
Raya divergent line.]
A right line drawn or extending from the center of a circle to the periphery; the semidiameter of a circle or sphere.
The preaxial bone of the forearm, or brachium, corresponding to the tibia of the hind limb. See Illust. of
☞ 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.
A ray, or outer floret, of the capitulum of such plants as the sunflower and the daisy. See
The barbs of a perfect feather.
Radiating organs, or color-markings, of the radiates.
The movable limb of a sextant or other angular instrument.
a bar pivoted at one end, about which it swings, and having its other end attached to a piece which it causes to move in a circular arc.–
Radius of curvature.
Webster 1828 Edition
1.In geometry, a right line drawn or extending from the center of a circle to the periphery, and hence the semidiameter of the circle. In trigonometry, the radius is the whole sine, or sine of 90 degrees.
2.In anatomy, the exterior bone of the fore arm, descending along with the ulna from the elbow to the wrist.
3.In botany, a ray; the outer part or circumference of a compound radiate flower, or radiated discous flower.