noun, plural radii vec·to·res [vek-tawr-eez, -tohr-] /vɛkˈtɔr iz, -ˈtoʊr-/, radius vectors.- Mathematics. the length of the line segment joining a fixed point or origin to a given point.
- Astronomy.
- 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.
- the distance between two such bodies at any point in the orbit.

## Origin of radius vector

First recorded in 1745–55

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British Dictionary definitions for radius vector- maths a line joining a point in space to the origin of polar or spherical coordinates
- astronomy an imaginary line joining a satellite to the planet or star around which it is orbiting

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

- A line segment that joins the origin and a variable point in a system of polar or spherical coordinates.
- 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.

The American Heritage® Science Dictionary
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