nuclear fission

[noo-klee-er fish-uhn]

noun

1. fission.

nuclear fission

noun

1. Sometimes shortened to: fission. the splitting of an atomic nucleus into approximately equal parts, either spontaneously or as a result of the impact of a particle usually with an associated release of energy Compare nuclear fusion

fission, nuclear

1. A nuclear reaction in which a single large nucleus splits into two or more smaller nuclei. In some cases, for example with uranium, energy is released in this process.

Pronunciation Note

See nuclear ( def. ).

The fission of uranium 235, an isotope of uranium, supplies energy for nuclear reactors and atomic bombs (see also atomic bomb).

Word History and Origins

Origin of nuclear fission¹

First recorded in 1885–90