astronomical unit astronomical telescope • astronomical year · · · Info · Definitions · Characters · · astronomical unit · · Text Common · · Latin · · Scripts 17 · · Length 7 · · Syllables Definitions · · · (noun) a unit of length used for distances within the solar system; equal to the mean distance between the Earth and the Sun (approximately 93 million miles or 150 million kilometers). Synonyms: Astronomical Unit, AU. · · Noun Definition 1 Characters · · space U+0020 a latin small letter a U+0061 c latin small letter c U+0063 i latin small letter i U+0069 l latin small letter l U+006C m latin small letter m U+006D n latin small letter n U+006E o latin small letter o U+006F r latin small letter r U+0072 s latin small letter s U+0073 t latin small letter t U+0074 u latin small letter u U+0075