Definition
The vernal equinox (♈, first point of Aries) is one of two intersection points of ecliptic and celestial equator — the one the Sun reaches in March when crossing northward. It is the origin of ecliptic longitude (0°) and right ascension (0h).
Precession
Due to precession the equinox regresses about 50″ per year along the ecliptic. The name 'Aries' is historical; the equinox now lies in Pisces.
