||Ra"di*us vec"tor (vĕk"tŏr).
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
coördinates. See Coördinate,
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.