Approaching to or departing from the center.

adjective. Deviating from circularity; changing the distance from a center.

adjective. a curve having the property that, when its plane is placed vertically, a body descending along it, by the force of gravity, will approach to, or recede from, a fixed point or center, by equal distances in equal times; -- called also a paracentric.

adjective. the motion or velocity of a revolving body, such as a planet, by which it approaches to, or recedes from, the center, without reference to its motion in space, or to its motion as reckoned in any other direction.

adjective. undefined

adjective. Deviating from circularity; changing the distance from a centre.

noun. A curve having the property that, when its plane is placed vertically, a body descending along it, by the force of gravity, will approach to, or recede from, a fixed point or centre, by equal distances in equal times.

"Complicating the matter further was the publication in 1689 of Leibniz's “Essay on the causes of celestial motions,” which offered a vortex theory in which “a planet moves with a double motion composed of the harmonic circulation of its fluid deferent orb, and the paracentric motion, as if it had a certain gravity of attraction, namely an impulsion towards the Sun” [L,"

paracentric motion  

paracentric velocity  paracentrical