Breadcrumb Home > Dictionary > Index H hour circle: Meaning and Definition of Find definitions for: hour' cir"cle Pronunciation: [key] — Astron. Astron. a great circle on the celestial sphere passing through the celestial poles and containing a point on the celestial sphere, as a star or the vernal equinox. Also called Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. hour angle hourglass ✖ Related Content Daily Word Quiz: musth Analogy of the Day: Today’s Analogy Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language