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
Through most of the Cold War, nuclear weapons and other weapons of mass destruction were, in bizarre ways, supposed to contribute to stability or even keep the peace.
—Literary Hub, 27 May 2026
Older kids can follow their interests to the various exhibits or to see the BA Concorde or the USS Grower, a nuclear submarine.
—Condé Nast, Condé Nast Traveler, 27 May 2026
Using electrical heaters to simulate nuclear fuel, PRECURSOR will demonstrate the working of the 30 MW reactor at a reduced scale.
—Ameya Paleja, Interesting Engineering, 27 May 2026
The report concluded by stressing that the Islamabad Framework remained unfinalized - and noting a significant possibility that the two sides could still fail to resolve their differences on terms to even begin direct negotiations on contentious issues such as Iran's nuclear material.
—CBS News, 27 May 2026
See All Example Sentences for nuclear
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Literary Hub, 27 May 2026
Older kids can follow their interests to the various exhibits or to see the BA Concorde or the USS Grower, a nuclear submarine.
—Condé Nast, Condé Nast Traveler, 27 May 2026
Using electrical heaters to simulate nuclear fuel, PRECURSOR will demonstrate the working of the 30 MW reactor at a reduced scale.
—Ameya Paleja, Interesting Engineering, 27 May 2026
The report concluded by stressing that the Islamabad Framework remained unfinalized - and noting a significant possibility that the two sides could still fail to resolve their differences on terms to even begin direct negotiations on contentious issues such as Iran's nuclear material.
—CBS News, 27 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 2 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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