Breadcrumb Home > Dictionary > Index S sun pillar: Meaning and Definition of Find definitions for: sun' pil"lar Pronunciation: [key] — Astron. Astron. a halo phenomenon in which a vertical streak of light appears above and below the sun, believed to be caused by the reflection of sunlight by ice crystals with vertical axes. Cf. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. sun parlor sun porch ✖ Related Content Daily Word Quiz: evanescent Analogy of the Day: Today’s Analogy Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language