thermonuclear

American  

[thur-moh-noo-klee-er, -nyoo-, -kyuh-ler] / ˌθɜr moʊˈnu kli ər, -ˈnyu-, -kyə lər /

adjective

1. of, relating to, or involving a thermonuclear reaction.

   thermonuclear power.

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thermonuclear British  

/ ˌθɜːməʊˈnjuːklɪə /

adjective

1. involving nuclear fusion

   a thermonuclear reaction

   thermonuclear energy

2. involving thermonuclear weapons

   a thermonuclear war

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thermonuclear Scientific  

/ thûr′mō-no̅o̅′klē-ər /

1. Relating to the fusion of atomic nuclei at high temperatures or to the energy produced in this way.

2. Relating to weapons based on nuclear fusion, especially as distinguished from those based on nuclear fission.

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thermonuclear Cultural  

1. A term referring to devices that use nuclear fusion, the fusion of atomic nuclei, to produce energy at very high temperatures. (See hydrogen bomb.)

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Pronunciation

See nuclear.

Etymology

Origin of thermonuclear

First recorded in 1935–40; thermo- + nuclear

Explanation

Something that has to do with high-temperature nuclear reactions is thermonuclear. Thermonuclear weapons are made using nuclear fusion. You'll almost always find the adjective thermonuclear describing the scientific process—it's a specific way to create fusion—or the resulting weapon. The word was first used around 1938 in reference to a process that occurs in stars. The first tests of a hydrogen bomb in the 1950s spawned the more common use of thermonuclear. The word combines the Greek thermos, "hot" and nuclear, "of the nucleus of a cell."

Example Sentences

He kept the U.S. out of any major war and developed a nuclear strategy that evolved from “massive retaliation” to a policy that recognized how an all-or-nothing approach to thermonuclear weapons would be too dangerous.

From The Wall Street Journal • Apr. 15, 2026

During his Nobel Peace Prize speech, Martin Luther King Jr. declared: “I refuse to accept the cynical notion that nation after nation must spiral down a militaristic stairway into the hell of thermonuclear destruction.”

From Salon • Oct. 6, 2024

Sure enough, when director Christopher Nolan asked him to emulate the sound of the world’s first thermonuclear device for “Oppenheimer,” King had his epic-scaled 2013 Chelyabinsk asteroid reference close at hand.

From Los Angeles Times • Feb. 13, 2024

Gopalaswamy says that direct-drive ICF is a promising approach for achieving thermonuclear ignition and net energy in laser fusion.

From Science Daily • Feb. 5, 2024

The program for Redwing included the first airborne drop of a thermonuclear device, which created an enormous fireball four miles in diameter when it detonated fifteen thousand feet over Bikini.

From "Big Science" by Michael Hiltzik