The difference between Fission and Fusion

Fission as a noun:

The process whereby one item splits to become two.

Fission as a noun (physics):

The process of splitting the nucleus of an atom into smaller particles; nuclear fission

Fission as a noun (biology):

The process by which a bacterium splits to form two daughter cells.

Fission as a verb (transitive):

To cause to undergo fission.

Fission as a verb (intransitive):

To undergo fission.

Fusion as a noun (physics):

The act of merging separate elements, or the result thereof. A nuclear reaction in which nuclei combine to form more massive nuclei with the concomitant release of energy. A style of music that blends disparate genres; especially types of jazz. A style of cooking that combines ingredients and techniques from different countries or cultures The act of melting or liquefying something by heating it. The result of the hybridation of two genes which originally coded for separate proteins. The process by which two distinct lipid bilayers merge their hydrophobic core, resulting in one interconnected structure. The act of two characters merging into one, typically more powerful, being; or the merged being itself.

Fusion as a verb (nonstandard):

to combine; to fuse