nuclear
adjective
nu·cle·ar ˈnü-klē-ər 
ˈnyü-
ˈnyü-
nonstandard -kyə-lər
1
: of, relating to, or constituting a nucleus
Annexation of the suburban fringe by the nuclear metropolis …—
W. H. Wickwar
W. H. Wickwar
2
a
: of or relating to the atomic nucleus
nuclear reaction
nuclear physics
b
: used in or produced by a nuclear reaction (such as fission)
nuclear fuel
nuclear waste
nuclear energy
c(1)
: being a weapon whose destructive power derives from an uncontrolled nuclear reaction
(2)
: of, produced by, or involving nuclear weapons
the nuclear age
nuclear war
(3)
: armed with nuclear weapons
nuclear powers
d
: of, relating to, or powered by nuclear energy
a nuclear submarine
the nuclear debate
a nuclear plant
see also:
How do you pronounce nuclear?: Usage Guide
Though disapproved of by many, pronunciations ending in \-kyə-lər\ have been found in widespread use among educated speakers including scientists, lawyers, professors, congressmen, U.S. cabinet members, and at least two U.S. presidents and one vice president. While most common in the U.S., these pronunciations have also been heard from British and Canadian speakers.
Examples of nuclear in a Sentence
Recent Examples on the Web
The scientists in question worked across specialties ranging from materials processing to the development of cancer drugs, only in some cases dealing with aerospace or nuclear matters. —Dan Adler, Vanity Fair, 22 Apr. 2026 Looming over the competition is the threat of nuclear annihilation that a calculating KGB agent warns his American counterpart is a very real danger if this contest doesn’t go off as planned. —Theater Critic, Los Angeles Times, 22 Apr. 2026 At least 12 other people, the vast majority involved in nuclear science and space research, have died or gone missing since 2022, some under mysterious circumstances. —Peter D'abrosca, FOXNews.com, 22 Apr. 2026 To replicate critical processes for future nuclear plants The facility is engineered to replicate the thermal cycles and hydraulic processes that will be utilized in future commercial nuclear power plants. —Aman Tripathi, Interesting Engineering, 22 Apr. 2026 See All Example Sentences for nuclear
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Dan Adler, Vanity Fair, 22 Apr. 2026 Looming over the competition is the threat of nuclear annihilation that a calculating KGB agent warns his American counterpart is a very real danger if this contest doesn’t go off as planned. —Theater Critic, Los Angeles Times, 22 Apr. 2026 At least 12 other people, the vast majority involved in nuclear science and space research, have died or gone missing since 2022, some under mysterious circumstances. —Peter D'abrosca, FOXNews.com, 22 Apr. 2026 To replicate critical processes for future nuclear plants The facility is engineered to replicate the thermal cycles and hydraulic processes that will be utilized in future commercial nuclear power plants. —Aman Tripathi, Interesting Engineering, 22 Apr. 2026 See All Example Sentences for nuclear
Video
'Mispronunciations' That May Be Fine
'Mischievous,' 'nuclear,' and other words to pronounce with caution.
Cite this Entry
“Nuclear.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.grautoblog.com/dictionary/nuclear. Accessed 24 Apr. 2026.
Copy CitationKids Definition
nuclear
adjective
nu·cle·ar ˈn(y)ü-klē-ər
1
: of, relating to, or being a nucleus (as of a cell)
2
: of, relating to, or using the atomic nucleus
nuclear reactions
3
: being or relating to energy or a weapon that involves a nuclear reaction
nuclear energy
a nuclear war
nuclear power plants
Medical Definition
nuclear
adjective
nu·cle·ar ˈn(y)ü-klē-ər
1
: of, relating to, or constituting a nucleus
2
: of, relating to, or utilizing the atomic nucleus, atomic energy, the atomic bomb, or atomic power
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