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nuclear energy

American  
[noo-klee-er en-er-jee, nyoo-] / ˈnu kli ər ˈɛn ər dʒi, ˈnju- /

noun

  1. energy released by reactions within atomic nuclei, as in nuclear fission or fusion.


nuclear energy British  

noun

  1. Also called: atomic energy.  energy released during a nuclear reaction as a result of fission or fusion

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

nuclear energy Scientific  
  1. The energy released by the nucleus of an atom as the result of nuclear fission, nuclear fusion, or radioactive decay. The amount of energy released by the nuclear fission of a given mass of uranium is about 2,500,000 times greater than that released by the combustion of an equal mass of carbon. And the amount of energy released by the nuclear fusion of a given mass of deuterium is about 400 times greater that that released by the nuclear fission of an equal mass of uranium.

  2. Also called atomic energy

  3. Electricity generated by a nuclear reactor.


nuclear energy Cultural  
  1. Energy obtained from nuclear reactions.


Pronunciation

See nuclear ( def. ).

Etymology

Origin of nuclear energy

First recorded in 1925–30

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

See Examples For:

Published in Nature, the findings offer new insight into the structure of atomic nuclei and could have important implications for astrophysics, nuclear energy, national security, and nuclear forensics.

From Science Daily Aug. 21, 2026

The four companies were defense technology companies Anduril Industries and Shield AI; Uber cofounder Travis Kalanick’s new venture, Atoms; and El Segundo-based nuclear energy startup Valar Atomics.

From Los Angeles Times Aug. 21, 2026

Ian Chun, senior research analyst at Sands Capital with $56 billion under management, commented that industrial companies in Korea were set to benefit from the build-out of power infrastructure, grid modernization and nuclear energy.

From MarketWatch Aug. 13, 2026

If the second reactor is shut down Romania will, like Hungary, be temporarily without any nuclear energy production.

From BBC Jul. 30, 2026

“It may be that the day of useful nuclear energy is not so far distant after all,” he wrote to his fellow cyclotron builder Alexander Allen.

From "Big Science" by Michael Hiltzik

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