sidereal day

Found in Anh - Anh (Wordnet)

Definition Noun : 1. A unit of time measurement : The sidereal day is the time it takes for the Earth to complete one full rotation on its axis relative to a distant, fixed star (or the vernal equinox), rather than relative to the Sun. It is approximately 23 hours, 56 minutes, and 4 seconds in mean solar time. Usage The term is used in astronomy, celestial navigation, and precise timekeeping to...