What is "radius vector"

Radius vector \Ra"di*us vec"tor\ (v[e^]k"t[o^]r).

1. (Math.) 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 co["o]rdinates. See Co["o]rdinate, n.

2. (Astron.) 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.

n. 1 (context mathematics English) 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. 2 (context astronomy English) 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.

1. n. a line connecting a satellite to the center of the body around which it is rotating

2. a line connecting a point in space to the origin of a polar coordinate system