核かく分ぶん裂れつ反はん応のうMeaningsNoun1. nuclear fission; fission reactionKanji used核nucleus分part裂split反be against応respond with actionComposed of核かく分ぶん裂れつnuclear fission; karyokinesis (division of a cell nucleus during mitosis or meiosis)Noun反はん応のうreaction; response; physical reaction (to a stimulus); observable response (of an organism); effect; changeNoun