核冬天 Traditional form: 核冬天 Pinyin (reading): hédōngtiān Definitions: nuclear winter Characters: 核 - core, kernel; nut, seed; atom 冬 - winter, 11th lunar month 天 - sky, heaven; god, celestial Traditional characters: 核 - core, kernel; nut, seed; atom 冬 - winter, 11th lunar month 天 - sky, heaven; god, celestial