fission

[fish-uhn]

noun

1. the act of cleaving or splitting into parts.

2. Also called nuclear fission. Physics.,  the splitting of the nucleus of an atom into nuclei of lighter atoms, accompanied by the release of energy.

3. Biology.,  the division of an organism into new organisms as a process of reproduction.

verb (used without object)

1. Physics.,  to undergo fission.

verb (used with object)

1. Physics.,  to cause to undergo fission.

fission

/ ˈfɪʃən /

noun

1. the act or process of splitting or breaking into parts

2. biology a form of asexual reproduction in single-celled animals and plants involving a division into two or more equal parts that develop into new cells

3. short for nuclear fission

fission

1. The splitting of an unstable atomic nucleus into two or more nuclei. Fission occurs spontaneously, generally when a nucleus has an excess of neutrons, resulting in the inability of the strong force to bind the protons and neutrons together. The fission reaction used in many nuclear reactors and bombs involves the absorption of neutrons by uranium-235 nuclei, which immediately undergo fission, releasing energy and fast neutrons.

2. Compare fusion

3. A process of asexual reproduction in which a single cell splits to form two identical, independent cells. In fission, the chromosomal DNA replicates before the cell divides. Most bacteria and other prokaryotes reproduce by means of fission.

4. Also called binary fission

Word History and Origins

Origin of fission¹

First recorded in 1835–45; from Latin fissiōn- (stem of fissiō ) “a splitting, dividing,” equivalent to fiss(us) “divided” + -iōn- noun-forming suffix; fissi-, -ion; fission def. 2 was first recorded in 1935–40

Word History and Origins

Origin of fission¹

C19: from Latin fissiō a cleaving

Example Sentences

And rather than burn it to release energy, they use nuclear fission, a process that unlocks the energy stored inside a tiny, tiny package: the nucleus of an atom.

Read more on Literature

As part of its energy surge, China has pushed rapid investment into the only technology that currently can decarbonize the planet at scale: nuclear fission and fusion.

Read more on The Wall Street Journal

Scientists realized that if they could break apart an atom’s nucleus, it would release energy as it split, a process they named fission.

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In the longer term, Google is looking toward nuclear fusion as opposed to fission: While the latter is used currently in power plants, the former can provide much more energy in a potentially safer process.

Read more on The Wall Street Journal

The vessel is the core of the reactor where fission takes place, and the only part of a nuclear plant that can’t be replaced.

Read more on The Wall Street Journal