/ Dictionary / Index S sidereal: Meaning and Definition of Find definitions for: si•de•re•al Pronunciation: (sī-dēr'ē-ul), [key] — adj. Astron. determined by or from the stars: sidereal time. of or pertaining to the stars. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: sidereal (Thesaurus) side pot sidereal day Related Content Daily Word Quiz: endear Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language