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. Wickwar2
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
Rubio said Iran has not made any concessions on its nuclear program that satisfy Washington and added that sanctions relief will hinge on Iran giving up its enriched uranium and dismantling its nuclear program.
—Francesca Chambers, USA Today, 4 June 2026
Russia has the most nuclear weapons, more than 5,400, followed by the US with almost 5,300.
—Brad Lendon, CNN Money, 4 June 2026
In 2025, Google followed suit, entering into an agreement with Kairos Power and the TVA for a new nuclear plant.
—Joseph Wilkins, CNBC, 3 June 2026
Khamenei previously vowed to protect Tehran’s nuclear enrichment capabilities, and Iranian officials have yet to officially announce a willingness to abandon them.
—Tiago Ventura, Time, 3 June 2026
See All Example Sentences for nuclear
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Francesca Chambers, USA Today, 4 June 2026
Russia has the most nuclear weapons, more than 5,400, followed by the US with almost 5,300.
—Brad Lendon, CNN Money, 4 June 2026
In 2025, Google followed suit, entering into an agreement with Kairos Power and the TVA for a new nuclear plant.
—Joseph Wilkins, CNBC, 3 June 2026
Khamenei previously vowed to protect Tehran’s nuclear enrichment capabilities, and Iranian officials have yet to officially announce a willingness to abandon them.
—Tiago Ventura, Time, 3 June 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.merriam-webster.com/dictionary/nuclear. Accessed 10 Jun. 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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