ˈnuːklijɚ 
British
ˈnjuːklijə
always used before a noun
1
a
: of, relating to, producing, or using energy that is created when the nuclei of atoms are split apart or joined together
nuclear [=atomic] weapons/bombs
a nuclear (power) plant
nuclear fuel
nuclear waste [=waste materials that are created when nuclear energy is produced]
b
: having or involving nuclear weapons
the nuclear [=atomic] age
a nuclear war/attack
nuclear powers [=countries that have nuclear weapons]
2
: of or relating to the nucleus of an atom
nuclear [=atomic] physics/fission/fusion
Cite this Entry
“Nuclear.” Merriam-Webster.com Simple Definition, Merriam-Webster, https://www.merriam-webster.com/simple/nuclear. Accessed 24 Jun. 2026.
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