1 (also ˌnuclear ˈfission) (in physics 物理学) the action or process of dividing the central part(nucleus)of an atom, when a large amount of energy is created 核裂变；核分裂 ☞Compare fusion. 与fusion比较。

2 (in biology 生物学) the division of cells into new cells as a method of creating more cells （细胞）分裂，裂殖