Equinox

Literally, the time of equal day and night. The point where the Celestial Equator and the Ecliptic intersect marks a point in space dividing the Celestial Sphere into North and South. When the Sun reaches this point in Declination, day and night are of almost equal length. This occurs twice a year as the Sun's apparent motion changes from north to south and south to north. This term is frequently, although incorrectly, used to describe a point lying on the Ecliptic.