Radius vector

вектор положения точки, радиус-вектор

Англо-русский научно-технический словарь

Radius vector

noun 1. a. the line segment or its length from a fixed point to a variable point b. the linear polar coordinate of a variable point 2. a straight line joining the center of an attracting body (as the sun) with that of a body (as a planet) in orbit around it

Merriam-Webster's Collegiate Dictionary