noun
: the interval between two successive transits of the March equinox over the upper meridian of a place that is equal to 23 hours, 56 minutes, 4.09 seconds of mean solar time — compare sidereal midnight
noun
: the interval between two successive transits of the March equinox over the upper meridian of a place that is equal to 23 hours, 56 minutes, 4.09 seconds of mean solar time — compare sidereal midnight
Webster's New International English Dictionary. Новый международный словарь английского языка Webster. 2012