tropical year; solar year
Astronomical term for the time it takes the Sun to return to the same position relative to the equinoxes, about 365.2422 days. Often contrasted with the sidereal year (恒星年).
See also: 太陽年
The tropical year is about 365.2422 days.
The Gregorian calendar was designed based on the tropical year.
Sidereal year; the time for the Earth to complete one orbit relative to the fixed stars, about 20 minutes longer than the tropical year.
Compound of 回帰 (return, recurrence) and 年 (year), referring to the Sun's return to the same equinoctial point.