Definition

The period of one REVOLUTION of the EARTH around the SUN, with respect to the VERNAL EQUINOX. Because of PRECESSION OF THE EQUINOXES, this is not 360° with respect to the STARS, but 50".3 less. A tropical year is about 20 minutes shorter than a SIDEREAL YEAR, averaging 365 DAYS, 5 HOURS, 48 MINUTES, and 46 SECONDS in 1900 and is decreasing at the rate of 0.005­30 second annually. Also called astronomical, equinoc­tial, natural, or solar year.