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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:

This resistance to environmental disturbances makes nuclear energy transitions especially promising for ultra-precise timekeeping.

From Science Daily ● Oct. 11, 2026

Regardless, investors likely haven’t seen the last big deal, and that’s driven meaningful recent gains for stocks tied to nuclear energy.

From MarketWatch ● Oct. 8, 2026

Amazon just made a new nuclear energy investment that could expand the capacity of America’s reactor fleet.

From Barron's ● Sep. 30, 2026

Roughly 50 companies are working on the small reactors, mostly in the U.S., said Adam Stein, director of nuclear energy and innovation at the Breakthrough Institute.

From Los Angeles Times ● Aug. 28, 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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