- a straight line joining the origin of a vector, located at the intersection of two coordinates, to a given point lying in the same plane
- a vector whose point of origin is fixed and whose terminal point ranges over a given curve or surface, as a straight line connecting the sun with the earth at any point of the earth's orbit
- Mathematics a. A line segment that joins the origin and a variable point in a system of polar or spherical coordinates.b. The length of such a line segment.
- Astronomy A straight line connecting the center of mass of a satellite, such as a planet, moon, or comet, to the center of mass of the body it orbits, such as the sun or Earth. Also called position vector.
(plural radius vectors)
- (mathematics) A straight line (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.
- (astronomy) 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.