sidereal year

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun The time required for one complete revolution of the earth about the sun, relative to the fixed stars, or 365 days, 6 hours, 9 minutes, 9.54 seconds in units of mean solar time.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun The orbital period of the Earth; a measure of the time it takes for the Sun to return to the same position with respect to the stars of the celestial sphere. A sidereal year is about 20.4 minutes longer than the tropical year due to precession of the equinoxes.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun the time for the earth to make one complete revolution around the sun, relative to the fixed stars