precession of the equinoxesprecession of the equinoxes
Astron. the occurrence of the equinoxes earlier in each successive sidereal year because of a slow wobble in the earth's axial spin which shifts the equinoctial points slightly westward along the ecliptic: the wobble is caused by the pull of the sun and moon on the earth's equatorial bulges and makes the poles move around a center point (axis of the ecliptic), taking about 25,800 years to return to the same orientation with the stars
precession of the equinoxes
A slow westward shift of the equinoxes along the plane of the ecliptic, resulting from precession of the earth's axis of rotation, and causing the equinoxes to occur earlier each sidereal year. The precession of the equinoxes occurs at a rate of 50.27 seconds of arc a year; a complete precession requires 25,800 years.