sidereal year(redirected from sidereal years)
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Related to sidereal years: anomalistic years
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.
(Astronomy) See year5
1. a period of 365 or 366 days, in the Gregorian calendar, divided into 12 calendar months, now reckoned as beginning Jan. 1 and ending Dec. 31 (calendar year). Compare common year, leap year.
2. a period of the same length in other calendars.
a. a space of 12 calendar months calculated from any point: We expect to finish in a year.
b. fiscal year.
a. Also called lunar year. a division of time equal to 12 lunar months.
b. Also called solar year. a division of time equal to 365 days, 5 hours, 48 minutes, and 46 seconds, representing the interval between one vernal equinox and the next.
c. Also called sidereal year. a division of time equal to the solar year plus 20 minutes, the time it takes the earth to complete one revolution around the sun.
5. the time in which any planet completes a revolution around the sun.
6. a full round of the seasons.
7. a period out of every 12 months devoted to a certain pursuit, activity, or the like: the academic year.
a. age: a person of her years.
b. old age: a man of years.
c. time; period: the years of hardship.
d. an unusually or markedly long time: We haven't spoken in years.
9. a group of students entering school or college, or those graduating in the same year; class.Idioms:
year in and year out, regularly through the years. Also, year in, year out.
[before 900; Middle English yeer, Old English gēar, c. Old Saxon, Old High German jār, Old Norse ār, Gothic jer; akin to Greek hôros year]
Equals the time that it takesthe Earth to revolve around the Sun from one fixed point (usually a star) back to the same point (365 days, 6 hr, 9 min, 9 sec).
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|Noun||1.||sidereal year - the time for the earth to make one complete revolution around the sun, relative to the fixed stars|
year - the period of time that it takes for a planet (as, e.g., Earth or Mars) to make a complete revolution around the sun; "a Martian year takes 687 of our days"
sidereal time - measured by the diurnal motion of stars