hour circle hour book • hourful · · · Info · Definitions · Characters · · hour circle · · Text Common · · Latin · · Scripts 11 · · Length 3 · · Syllables Definitions · · · (noun) a great circle on the celestial sphere that passes through both celestial poles. Synonyms: hour circle. · · Noun Definition 1 Characters · · space U+0020 c latin small letter c U+0063 e latin small letter e U+0065 h latin small letter h U+0068 i latin small letter i U+0069 l latin small letter l U+006C o latin small letter o U+006F r latin small letter r U+0072 u latin small letter u U+0075