Quantcast
Merriam-Webster Logo
  • Dictionary
  • Thesaurus
  • Scrabble
  • Spanish Central
  • Learner's Dictionary

sidereal day

noun

Definition of sidereal day

  1. :  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



1764

First Known Use of sidereal day

1764


Learn More about sidereal day


Seen and Heard

What made you want to look up sidereal day? Please tell us where you read or heard it (including the quote, if possible).

WORD OF THE DAY

looking or feeling very sad

Get Word of the Day daily email!