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• nuclear fusion
  nuclear fusion

  noun

  fusion.
• fusion, nuclear
  fusion, nuclear

  The combining of two small atomic nuclei to form a larger nucleus, sometimes with the release of energy. (Compare nuclear fission.)

nuclear fusion

American  

[noo-klee-er fyoo-zhuhn, nyoo-] / ˈnu kli ər ˈfju ʒən, ˈnju- /

noun

1. fusion.

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nuclear fusion British  

noun

1. Sometimes shortened to: fusion.  a reaction in which two nuclei combine to form a nucleus with the release of energy Compare nuclear fission See also thermonuclear reaction

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fusion, nuclear Cultural  

1. The combining of two small atomic nuclei to form a larger nucleus, sometimes with the release of energy. (Compare nuclear fission.)

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Pronunciation

See nuclear ( def. ).

Discover More

The use of fusion as a controllable energy source on Earth is still in its experimental stages.

The fusion of hydrogen into helium releases huge amounts of energy and is the main energy source of stars, including the sun.

Hydrogen bombs use the energy of fusion.

Etymology

Origin of nuclear fusion

First recorded in 1895–1900

Example Sentences

See Examples For:

nuclear fusion fusion, nuclear

This chemical makeup closely resembles the composition of the young universe, when almost all matter consisted of hydrogen and helium and heavier elements were only beginning to form inside massive stars through nuclear fusion.

From Science Daily ● Jul. 5, 2026

And helium-3 could also be used in some nuclear fusion reactors to one day create vast amounts of clean energy.

From BBC ● Jun. 16, 2026

Massive stars produce light and heat through nuclear fusion, a process that releases enormous amounts of energy from their cores.

From Science Daily ● Jun. 14, 2026

She previously covered big oil and gas companies and reported on low-carbon technologies, such as green hydrogen and nuclear fusion.

From The Wall Street Journal ● May 13, 2026

When we look up at night and view the stars, everything we see is shining because of distant nuclear fusion.

From "Cosmos" by Carl Sagan

For 75 years the U.S. federal government has invested heavily in fission and fusion nuclear power with only modest gains to show.

From Scientific American ● Jun. 5, 2023

Finally, fusion nuclear energy has achieved a breakthrough, thanks to the federal government and the work by some Seattle startups.

From Seattle Times ● Apr. 28, 2023

Its venture capital arm, Chevron Technology Ventures, is investing in new-energy start-ups like Zap Energy, which is developing modular fusion nuclear reactors that release no greenhouse gases and limit radioactive waste.

From New York Times ● Sep. 21, 2020