is a splitting of something into two parts.
Fission may refer to:
- In physics, nuclear fission is a process where a large atomic nucleus (such as uranium) is split into two smaller nuclei
- In biology, binary fission is the mitosis process whereby a prokaryote reproduces by cell division
- In anthropology, fission is the process whereby a nation-state divides and becomes multiple states
- In geology, fissility is the property of mudstones to split along layers