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
Wang also said China appreciates Iran’s pledge to not develop nuclear weapons, while acknowledging Iran's legitimate right to peaceful use of nuclear energy.
—ABC News, 6 May 2026
As the years progressed, Turner created the Nuclear Threat Initiative to secure loose nuclear weapons in the former Soviet republics and elsewhere.
—David Folkenflik, NPR, 6 May 2026
An environmental nuclear bomb looms in Utah.
—Matthew Carey, Deadline, 6 May 2026
After an initial draft that referenced nuclear war and God-like beings was edited by Charles Monteith, the copy gradually became a critical success, selling more than 10 million copies to date.
—Connor Sturges, Condé Nast Traveler, 6 May 2026
See All Example Sentences for nuclear
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ABC News, 6 May 2026
As the years progressed, Turner created the Nuclear Threat Initiative to secure loose nuclear weapons in the former Soviet republics and elsewhere.
—David Folkenflik, NPR, 6 May 2026
An environmental nuclear bomb looms in Utah.
—Matthew Carey, Deadline, 6 May 2026
After an initial draft that referenced nuclear war and God-like beings was edited by Charles Monteith, the copy gradually became a critical success, selling more than 10 million copies to date.
—Connor Sturges, Condé Nast Traveler, 6 May 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 7 May. 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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