noun Date: 1764 the interval between two successive transits of a point on the celestial sphere (as the vernal equinox) over the upper meridian of a place ; 23 hours, 56 minutes, 4.1 seconds of mean time
SIDEREAL DAY
Meaning of SIDEREAL DAY in English
Merriam Webster. Explanatory English dictionary Merriam Webster. Толковый словарь английского языка Мерриам-Уэбстер. 2012