radius vector > define

noun

• A line connecting a satellite to the center of the body around which it is rotating.
• A line connecting a point in space to the origin of a polar coordinate system. .

• (n.) An ideal straight line joining the center of an attracting body with that of a body describing an orbit around it, as a line joining the sun and a planet or comet or a planet and its satellite.
• A straight line (or the length of such line) connecting any point, as of a curve, with a fixed point or pole, round which the straight line turns, and to which it serves to refer the successive points of a curve, in a system of polar coordinates. See Coordinate, n.