pl. radii vectores /vek tawr"eez, -tohr"-/ , radius vectors .
1. Math. the length of the line segment joining a fixed point or origin to a given point.
2. Astron.
a. 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.
b. the distance between two such bodies at any point in the orbit.
[ 1745-55 ]