sun gear sung dynasty • sun gem · · · Info · Definitions · Characters · · sun gear · · Text Common · · Latin · · Scripts 8 · · Length 2 · · Syllables Definitions · · · (noun) the central gear in an epicyclic train. Synonyms: sun gear. · · Noun Definition 1 Characters · · space U+0020 a latin small letter a U+0061 e latin small letter e U+0065 g latin small letter g U+0067 n latin small letter n U+006E r latin small letter r U+0072 s latin small letter s U+0073 u latin small letter u U+0075