Definitions
1.nounThe time it takes the Earth to pass once around the Sun, as reckoned with respect to the seasons and not the fixed stars (for instance from vernal equinox to vernal equinox).
2.noun(by extension) The 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.