Radius

Part of speech: noun (n.)

1. A right line drawn or extending from the center of a circle to the periphery; the semidiameter of a circle or sphere.

2. The preaxial bone of the forearm, or brachium, corresponding to the tibia of the hind limb. See Illust. of Artiodactyla.

3. A ray, or outer floret, of the capitulum of such plants as the sunflower and the daisy. See Ray, 2.

4. The barbs of a perfect.

5. Radiating organs, or color-markings, of the radiates.

6. The movable limb of a sextant or other angular instrument. Knight. Radius bar (Math.), 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. See under Curvature.