radius vector

noun

, plural radii vec·to·res [vek-, tawr, -eez, -, tohr, -], radius vectors.

1. Mathematics. the length of the line segment joining a fixed point or origin to a given point.
2. Astronomy.
   1. the straight line joining two bodies in relative orbital motion, as the line from the sun to a planet at any point in its orbit.
   2. the distance between two such bodies at any point in the orbit.

radius vector

noun

1. maths a line joining a point in space to the origin of polar or spherical coordinates
2. astronomy an imaginary line joining a satellite to the planet or star around which it is orbiting

radius vector

1. A line segment that joins the origin and a variable point in a system of polar or spherical coordinates.
2. The imaginary straight line that connects the center of the Sun or another body with the center of a planet, comet, or other body that orbits it.

Word History and Origins

Origin of radius vector¹

First recorded in 1745–55

Example Sentences

In a curve referred to polar co”rdinates, any point for which the radius vector is a maximum or minimum.

From Project Gutenberg

So Kepler formulated his second great law of planetary motion very simply: the radius vector of any planet describes, or sweeps over, equal areas in equal times.

From Project Gutenberg

Pōlar-co-or′dinates, co-ordinates defining a point by means of a radius vector and the angle which it makes with a fixed line through the origin; Pō′lar-for′ces, forces that act in pairs and in different directions, as in magnetism.—n.

From Project Gutenberg

Hodograph, hod′o-graf, n. a curve the radius vector of which represents in direction and magnitude the velocity of a moving particle—a term suggested by Sir W. R. Hamilton.

From Project Gutenberg

He fiercely opposed the second, maintaining and demonstrating by means of a most brilliant calculation that the areas described by the radius vector are not in any degree equal to the time employed in making them, but they concord with the attractive or repulsive force of the celestial bodies.

From Project Gutenberg