/ Dictionary / Index S solar apex: Meaning and Definition of Find definitions for: so'lar a'pex Pronunciation: [key] — Astron. Astron. the point on the celestial sphere, near Vega, toward which the solar system is moving relative to the visible stars. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. solar activity solar battery Related Content Daily Word Quiz: paradox Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language