noun
: a uniform measure of time defined by the orbital motions of the planets and determined by correcting mean solar time for the irregularities arising from variations in the rate of rotation of the earth
noun
: a uniform measure of time defined by the orbital motions of the planets and determined by correcting mean solar time for the irregularities arising from variations in the rate of rotation of the earth
Webster's New International English Dictionary. Новый международный словарь английского языка Webster. 2012