nuclear

adjective

nu·​cle·​ar ˈnü-klē-ər  ˈnyü- 

 nonstandard  -kyə-lər

1

: of, relating to, or constituting a nucleus

annexation of the suburban fringe by the nuclear metropolis

—W. H. Wickwar

2

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

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.

Phrases

go nuclear

informal

: to become wildly excited or upset : go berserk

To say the crowd went wild is an understatement. The crowd went nuclear. Outside the stadium, cars were overturned and fires were set. We sportswriters huddled inside, fearing for our lives.

—Tony Kornheiser

Examples of nuclear in a Sentence

Recent Examples on the Web

The project is based on the story of a whistleblower who claimed Israel was building a nuclear weapons program. —K.j. Yossman, Variety, 25 Apr. 2024

Researchers were building out a global network of seismographs, which measure ground motion, to monitor nuclear weapons testing. —Christian Elliott, Smithsonian Magazine, 24 Apr. 2024

The coordinated diplomacy and pressure from Russia and the West that brought Iran into the 2015 nuclear deal are now a distant memory. —Andrea Kendall-Taylor, Foreign Affairs, 23 Apr. 2024

In the 1998 hit Armageddon, which Bruckheimer produced, NASA enlists a group of oil drillers to fly into space, land on a massive asteroid that’s hurtling towards Earth, drill into the rock and insert a nuclear bomb to destroy it. —Eric Andersson, Peoplemag, 23 Apr. 2024

Last year, Christopher Nolan’s Oppenheimer and Martin Scorsese’s Killers of the Flower Moon confronted the ghosts of American brutality, from the decision to drop a nuclear weapon to the genocide of indigenous communities. —David Rooney, The Hollywood Reporter, 23 Apr. 2024

In 2023, electricity from wind and solar was significantly less expensive than from coal, nuclear and natural gas. —Elizabeth Weise, USA TODAY, 22 Apr. 2024

The 2015 Iran nuclear deal brokered by the Obama administration and several other nations limited the country's nuclear capabilities, but the Trump administration withdrew from the accord. —Joy Burton, NBC News, 20 Apr. 2024

The strikes in Iran’s Isfahan province — which is where Natanz, one of Iran's nuclear facilities, is located — come in retaliation for Iran firing a barrage of missiles and drones at Israel last Saturday. —Greg Norman, Fox News, 19 Apr. 2024

Word History

Etymology

nucle(us) + -ar

First Known Use

1822, in the meaning defined at sense 1

Phrases Containing nuclear

• go nuclear
• nuclear capability
• nuclear energy
• nuclear family
• nuclear fission
• nuclear-free
• nuclear fusion
• nuclear magnetic resonance
• nuclear medicine
• nuclear membrane
• nuclear option
• nuclear power
• nuclear reaction
• nuclear reactor
• nuclear sap
• nuclear winter
• post-nuclear

Video

'Mispronunciations' That May Be Fine

'Mischievous,' 'nuclear,' and other words to pronounce with caution.

Kids 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