Definitions for "Sidereal year"
Keywords:  revolution, star, sun, orbit, earth
The time required for the Earth to move around its orbit, relative to the fixed stars. Equal to the time required for the Sun to move around the Ecliptic, relative to the fixed stars.
the time required for the Earth to complete an exactly 360° orbit around the Sun as measured with respect to the stars = 365.2564 mean solar days (contrast with tropical year).
The time required for one complete revolution of the earth around the sun, relative to the fixed stars, or 365 days, 6 hours, 9 minutes, 9.54 seconds in units of mean solar time.