sidereal hour sidereal day • sidereal month · · · Info · Definitions · Characters · · sidereal hour · · Text Common · · Latin · · Scripts 13 · · Length 4 · · Syllables Definitions · · · (noun) 1/24 of a sidereal day. Synonyms: sidereal hour. · · Noun Definition 1 Characters · · space U+0020 a latin small letter a U+0061 d latin small letter d U+0064 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 s latin small letter s U+0073 u latin small letter u U+0075