precession of the equinoxes : The conical movement of the Earth s axis about the vertical to the plane of the ecliptic caused by gravitational forces of the Sun, Moon and other planets, and resulting in the continual change of the position of vernal equinox along the celestial equator;
(the ecliptic; caused; by gravitational forces of the Sun, Moon and other planets)
the ecliptic
caused
by gravitational forces of the Sun, Moon and other planets