資料來源 : pyDict
等分線
資料來源 : Webster's Revised Unabridged Dictionary (1913)
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.
Being of middle age and a mean stature. --Sir. P.
Sidney.
2. Intermediate in excellence of any kind.
According to the fittest style of lofty, mean, or
lowly. --Milton.
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.
{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, especially by
European writers, {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.