/ Dictionary / Index S sidereal month: Meaning and Definition of Find definitions for: side'real month' Pronunciation: [key] — Astron. Astron. See under(def. 5). Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. sidereal hour angle sidereal time 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