Learner's definition of FISSION
[noncount]
1
physics : a process in which the nucleus of a heavy atom is split apart(原子核的)分裂,裂变 ◊ A large amount of energy is released when fission occurs.核裂变发生时,释放出巨大的能量。
— called also nuclear fission
— compare fusion 2
biology : a kind of reproduction in which a cell or body divides into two or more parts and each part grows into a whole new individual细胞分裂;裂体生殖