Fission 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 particles.
- In biology, fission (biology) is the subdivision of a cell or a multi-cellular body into one or more parts and the regeneration of each of the parts into a complete individual.
- In anthropology, fission is the process whereby a nation-state divides and becomes multiple states