Mean sun
Mean Mean, a. [OE. mene, OF. meiien, F. moyen, fr. L. medianus that is in the middle, fr. medius; akin to E. mid. See {Mid}.] 1. Occupying a middle position; middle; being about midway between extremes. [1913 Webster]

Being of middle age and a mean stature. --Sir. P. Sidney. [1913 Webster]

2. Intermediate in excellence of any kind. [1913 Webster]

According to the fittest style of lofty, mean, or lowly. --Milton. [1913 Webster]

3. (Math.) Average; having an intermediate value between two extremes, or between the several successive values of a variable quantity during one cycle of variation; as, mean distance; mean motion; mean solar day. [1913 Webster]

{Mean distance} (of a planet from the sun) (Astron.), the average of the distances throughout one revolution of the planet, equivalent to the semi-major axis of the orbit.

{Mean error} (Math. Phys.), the average error of a number of observations found by taking the mean value of the positive and negative errors without regard to sign.

{Mean-square error}, or {Error of the mean square} (Math. Phys.), the error the square of which is the mean of the squares of all the errors; -- called also, {mean square deviation}, {mean error}.

{Mean line}. (Crystallog.) Same as {Bisectrix}.

{Mean noon}, noon as determined by mean time.

{Mean proportional} (between two numbers) (Math.), the square root of their product.

{Mean sun}, a fictitious sun supposed to move uniformly in the equator so as to be on the meridian each day at mean noon.

{Mean time}, time as measured by an equable motion, as of a perfect clock, or as reckoned on the supposition that all the days of the year are of a mean or uniform length, in contradistinction from apparent time, or that actually indicated by the sun, and from sidereal time, or that measured by the stars. [1913 Webster]


The Collaborative International Dictionary of English. 2000.

Look at other dictionaries:

  • mean sun — n. Astron. a hypothetical sun thought of as moving uniformly along the celestial equator at a speed equal to the actual sun s average speed along the ecliptic: hypothesized as a basis for keeping time, because the actual sun does not travel along …   English World dictionary

  • mean sun — mean′ sun′ n. astron. an imaginary sun moving uniformly in the celestial equator and taking the same time to make its annual circuit as the true sun does in the ecliptic …   From formal English to slang

  • mean sun — noun a theoretical sun that moves along the celestial equator at a constant speed and completes its annual course in the same amount of time the real sun takes at variable speeds • Hypernyms: ↑model, ↑theoretical account, ↑framework * * * noun… …   Useful english dictionary

  • mean sun — An imaginary body which is assumed to travel around the equinoctial at a constant rate, completing one orbit in the same time that the earth takes to complete one orbit around the ecliptic. Because of the elliptical shape of the earth’s orbit,… …   Aviation dictionary

  • mean sun — noun an imaginary sun conceived as moving at a constant speed equal to the mean rate of the real sun, used in calculating solar time …   English new terms dictionary

  • mean sun — /min ˈsʌn/ (say meen sun) noun an imaginary sun moving uniformly in the celestial equator and taking the same time to make its annual circuit as the true sun does in the ecliptic …   Australian English dictionary

  • mean sun — noun Date: 1765 a fictitious sun used for timekeeping that moves uniformly along the celestial equator and maintains a constant rate of apparent motion equal to the average rate of apparent motion of the real sun …   New Collegiate Dictionary

  • mean sun — Astron. an imaginary sun moving uniformly in the celestial equator and taking the same time to make its annual circuit as the true sun does in the ecliptic. * * * …   Universalium

  • mean sun — See mean solar time …   Ballentine's law dictionary

  • mean sun time — See mean solar time …   Ballentine's law dictionary

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