/ Dictionary / Index S siderostat: Meaning and Definition of Find definitions for: sid•er•o•stat Pronunciation: (sid'ur-u-stat"), [key] — n. a telescopic device for reflecting the light of a star in a constant direction, the chief component of which is a plane mirror turned by a clock mechanism to correct for the rotation of the earth. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. siderosis sidesaddle Related Content Daily Word Quiz: pudgy Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language