nu·​cle·​ar | \ ˈnü-klē-ər How to pronounce nuclear (audio) , ˈnyü- How to pronounce nuclear (audio) , nonstandard -kyə-lər\

Definition of nuclear

1 : of, relating to, or constituting a nucleus annexation of the suburban fringe by the nuclear metropolis— W. H. Wickwar
2a : 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
go nuclear
: to become wildly excited or upset : to 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

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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

The center addresses such national security risks as financing terrorism and nuclear threats. Washington Post, "Indicted Canadian intelligence official had access to allies’ secrets, official says," 18 Sep. 2019 Unfortunately for these Glendale, California, students, a nuclear blast happens to arrive just in time for the homecoming dance, and in the aftermath, the high school and all of its students have to band together to survive. Lauren Rearick, Teen Vogue, "Netflix's "Daybreak" Releases First Trailer for the Apocalyptic High School Drama," 16 Sep. 2019 In order to identify a person, nuclear DNA is required. Heather Murphy, New York Times, "Why This Scientist Keeps Receiving Packages of Serial Killers’ Hair," 16 Sep. 2019 The whole purpose of the ballistic missile defense system is for ballistic missile, nuclear missile defense. Paul Gattis |, al, "How Huntsville helps protect U.S. from potential nuclear attack," 12 Sep. 2019 The experts, including former military leaders, ambassadors and members of Congress, cited a nuclear North Korea, an increasingly hostile Iran and a combative Russia as some of the biggest threats still facing the United States. Sam Tabachnik, The Denver Post, "Colorado leaders commemorate 9/11 anniversary," 11 Sep. 2019 In the mid-1990s boy scout David Hahn used household objects and his scientific knowledge to start building a nuclear reactor in his backyard. Matthew Gault, Scientific American, "3-D Printers Could Help Spread Weapons of Mass Destruction," 10 Sep. 2019 Another reason for the April 3 release date, according to the Reddit user, is that season 4 is supposed to take place in 1986, presumably, the year of the Chernobyl disaster, a nuclear accident that occurred in April 1986. Jasmine Gomez, Seventeen, "This "Stranger Things" Fan Thinks He's Figured Out When the Next Season Will Be Released," 9 Sep. 2019 After the Explosion: Documenting Chernobyl Sept. 14-Feb. 23: These photos of the cleanup of the Chernobyl nuclear disaster in northwestern Ukraine in the last 1980s are from the archive of Maj. Kathy Berdan, Twin Cities, "Fall Arts Guide: What to see at Twin Cities museums," 7 Sep. 2019

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'nuclear.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of nuclear

1822, in the meaning defined at sense 1

History and Etymology for nuclear

nucle(us) + -ar

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Statistics for nuclear

Last Updated

5 Oct 2019

Look-up Popularity

Time Traveler for nuclear

The first known use of nuclear was in 1822

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English Language Learners Definition of nuclear

: of, relating to, producing, or using energy that is created when the nuclei of atoms are split apart or joined together
: having or involving nuclear weapons
: of or relating to the nucleus of an atom


nu·​cle·​ar | \ ˈnü-klē-ər How to pronounce nuclear (audio) , ˈnyü-\

Kids Definition of nuclear

1 : of, relating to, or being a nucleus (as of a cell)
2 : of or relating to the nucleus of the atom Fission is a nuclear reaction.
3 : produced by a nuclear reaction nuclear energy
4 : of, relating to, or being a weapon whose destructive power comes from an uncontrolled nuclear reaction
5 : relating to or powered by nuclear energy a nuclear submarine


nu·​cle·​ar | \ ˈn(y)ü-klē-ər How to pronounce nuclear (audio) \

Medical Definition of nuclear

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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More from Merriam-Webster on nuclear

Spanish Central: Translation of nuclear

Nglish: Translation of nuclear for Spanish Speakers

Britannica English: Translation of nuclear for Arabic Speakers

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