Fission

[Sarah]

A method of asexual reproduction among the lowest (unicellular)organisms by means of a process of self-division, consisting ofgradual division or cleavage of the into two parts, each of whichthen becomes a separate and independent organisms; as when a cell inan animal or plant, or its germ, undergoes a spontaneous division,and the parts again subdivide. See Segmentation, and Cell division,under Division.

[Sarah]

Fission is the splitting of one, tangible or intangible, into two or more new things that possess either properties from one or the other. In physics it is the splitting of one element to create two or more new ones. Splitting a single Helium atom into two Hydrogen atoms.

[Dianne]

the process of dividing the nucleus of an atom, resulting in the release of a large amount of energy :

[Lizzy Liz]

The action of dividing or splitting something into two or more parts.