RADIUS VECTOR • FREE TRANSLATOR.ORG • Definition of Radius vector

... simply a misuse of language. It would really be interesting if the Duke of Argyll would explain how he proposes to set about showing that the elliptical form of the orbits of the planets, the constant area described by the radius vector, and the proportionality of the squares of the periodic times to the cubes of the distances from the sun, are either caused by the "force of gravitation" or deducible from the "law of gravitation." ...

— Collected Essays, Volume V - Science and Christian Tradition: Essays • T. H. Huxley