Définitions
1.NounThe time that it takes for the Sun to return to the same position along the ecliptic, as viewed from the Earth, especially, completing a full cycle of seasons.
2.NounA vernal equinox year; the time between two successive vernal equinoxes.
3.NounThe time it takes for any astronomical object (such as a planet, dwarf planet, small Solar System body, or comet) in direct orbit around a star (such as the Sun) to make one revolution around the star, taking into account orbital precession.