noun

1. a splitting apart; division into parts
2. nuclear fission
3. Biol. a form of asexual reproduction, found in various simple plants and animals, in which the parent organism divides into two or more approximately equal parts, each becoming an independent individual

Etymology: L fissio < fissus, pp. of findere, to cleave, split < IE base *bheid-, to split > bite

intransitive verb, transitive verb