- 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 Artiodactyla.
- A ray, or outer floret, of the capitulum of such plants as the sunflower and the daisy. See Ray, 2.
- The barbs of a perfect feather.
- Radiating organs, or color-markings, of the radiates.
- The movable limb of a sextant or other angular instrument.