Breadcrumb Home > Dictionary > Index H heliostat: Meaning and Definition of Find definitions for: he•li•o•stat Pronunciation: (hē'lē-u-stat"), [key] — n. an instrument consisting of a mirror moved by clockwork, for reflecting the sun's rays in a fixed direction. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. heliosphere heliotaxis ✖ Related Content Daily Word Quiz: rocrustean Analogy of the Day: Today’s Analogy Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language