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
As geopolitical tensions and concerns over nuclear proliferation continue to evolve, the development of ATOLL represents a strategic investment in America’s ability to detect, understand, and prevent the misuse of nuclear technology.
—Prabhat Ranjan Mishra, Interesting Engineering, 10 June 2026
Furthermore, Iran has yet to make major concessions related to its nuclear capabilities and desire to manage naval navigation in the Strait of Hormuz.
—Callum Sutherland, Time, 10 June 2026
The leaders of China and North Korea reaffirmed their alliance this week in Pyongyang, emphasizing strategic cooperation while avoiding public discussion of North Korea's nuclear weapons program.
—Jennifer Pak, NPR, 10 June 2026
For his part, Merz has openly questioned whether developing a manned sixth-generation fighter jet still made sense for his country’s air force, and said Germany did not need a nuclear-capable jet that could land on an aircraft carrier.
—CNN Money, 9 June 2026
See All Example Sentences for nuclear
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Prabhat Ranjan Mishra, Interesting Engineering, 10 June 2026
Furthermore, Iran has yet to make major concessions related to its nuclear capabilities and desire to manage naval navigation in the Strait of Hormuz.
—Callum Sutherland, Time, 10 June 2026
The leaders of China and North Korea reaffirmed their alliance this week in Pyongyang, emphasizing strategic cooperation while avoiding public discussion of North Korea's nuclear weapons program.
—Jennifer Pak, NPR, 10 June 2026
For his part, Merz has openly questioned whether developing a manned sixth-generation fighter jet still made sense for his country’s air force, and said Germany did not need a nuclear-capable jet that could land on an aircraft carrier.
—CNN Money, 9 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 16 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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