Definition of: radius vector

plural radius vectors or ra·di·i vec·to·res (rā′dē·ī vek·tôr′ēz, -tō′rēz)
1. Math. a The distance from a fixed origin to any point of a curve. b The distance from a point to the pole in the polar coordinate or spherical coordinate system.
2. Astron. A line from a center of attraction to a body describing an orbit about it.