atomic bomb

American  

[uh-tom-ik bom] / əˈtɒm ɪk ˌbɒm /

Also atom bomb

noun

1. a bomb whose potency is derived from nuclear fission of atoms of fissionable material with the consequent conversion of part of their mass into energy.

2. a bomb whose explosive force comes from a chain reaction based on nuclear fission in U-235 or plutonium.

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atomic bomb British  

noun

1. Also called: A-bomb.   fission bomb.  a type of bomb in which the energy is provided by nuclear fission. Uranium-235 and plutonium-239 are the isotopes most commonly used in atomic bombs Compare fusion bomb

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atomic bomb Scientific  

1. A very destructive bomb that derives its explosive power from the fission of atomic nuclei. Atomic bombs usually have plutonium 239 or uranium 235 as their fissionable material.

2. Also called atom bomb

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atomic bomb ¹ Cultural  

1. A bomb that is powered by nuclear fission, and therefore produces a quick release of energy and great destruction.

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atomic bomb ² Cultural  

1. A nuclear weapon whose enormous explosive power results from the sudden release of energy from a fission reaction. (See also Hiroshima (see also Hiroshima), hydrogen bomb, Nagasaki, and Strategic Arms Limitation Talks [SALT].)

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Etymology

Origin of atomic bomb

First recorded in 1910–15

Compare meaning

How does atomic-bomb compare to similar and commonly confused words? Explore the most common comparisons:

• hydrogen bomb vs. atomic bomb
• hydrogen vs. atomic bomb

Example Sentences

Casias had been an administrative assistant at Los Alamos National Laboratory, where the first atomic bomb was developed and where nuclear weapon work continues, her family told local news outlets after her disappearance.

From Los Angeles Times • Jun. 2, 2026

Recently, survivors of the Hiroshima atomic bomb pressed for the abolition of nuclear arms at the United Nations, calling to build a human society free from nuclear weapons and war.

From BBC • May 7, 2026

Iran denies seeking a nuclear weapon and the UN nuclear watchdog says that an atomic bomb was not imminent before the war.

From Barron's • Apr. 23, 2026

Not to be confused with movies about Fox News or Hedy Lamarr, “Bombshell” isn’t just a film about the atomic bomb either.

From The Wall Street Journal • Dec. 31, 2025

The Soviets responded in August 1949 with a successful test of their first atomic bomb.

From "Fallout: Spies, Superbombs, and the Ultimate Cold War Showdown" by Steve Sheinkin

Related Words

• atom bomb
• hydrogen bomb
• neutron bomb
• nuclear warhead