light hour light-horseman • lighthouse · · · Info · Definitions · Characters · · light hour · · Text Common · · Latin · · Scripts 10 · · Length 2 · · Syllables Definitions · · · (noun) the distance light travels in a vacuum in one hour; approximately one billion kilometers. Synonyms: light hour. · · Noun Definition 1 Characters · · space U+0020 g latin small letter g U+0067 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 t latin small letter t U+0074 u latin small letter u U+0075