白垩纪 bái'èjì Cretaceous period Origin Definitions Defs Strokes Stroke Words Sentences Sents 白垩 白堊 bái'è chalk chalk; a soft, white, porous limestone consisting mainly of calcium carbonate纪 紀 jì noun era (bound form) a period of time, such as a twelve-year cycle, a geological period, or a century; era