n. & adj.
n. 1 a condition, quality, virtue, or course of action equally removed from two opposite (usu. unsatisfactory) extremes. 2 Math. a the term or one of the terms midway between the first and last terms of an arithmetical or geometrical etc. progression (2 and 8 have the arithmetic mean 5 and the geometric mean 4). b the quotient of the sum of several quantities and their number, the average.
adj. 1 (of a quantity) equally far from two extremes. 2 calculated as a mean. mean free path the average distance travelled by a gas molecule etc. between collisions. mean sea level the sea level halfway between the mean levels of high and low water. mean sun an imaginary sun moving in the celestial equator at the mean rate of the real sun, used in calculating solar time. mean time the time based on the movement of the mean sun.
[ ME f. AF meen f. OF meien, moien f. L medianus MEDIAN ]