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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.

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

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
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

atomic bomb 1 Cultural  

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

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].)

Etymology

Origin of atomic bomb

First recorded in 1910–15

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Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

Ms. Gage deals with it by visiting the remnants of a Japanese internment camp at Manzanar, Calif., and the research facility in Los Alamos, N.M., where U.S. government scientists built the atomic bomb.

From The Wall Street Journal • Apr. 1, 2026

“The Most Awful Responsibility” sympathetically portrays Truman’s conflicted soul over the mass death inflicted by the atomic bomb.

From The Wall Street Journal • Jan. 16, 2026

The specter of Nazism has always loomed large over the atomic bomb.

From Salon • Aug. 14, 2025

"On 9 August 1945 an atomic bomb was dropped on this city," Suzuki said in the declaration.

From BBC • Aug. 9, 2025

“Back on Tinian, the second atomic bomb was being assembled even as the world was learning about the first,” remembered Paul Tibbets.

From "Bomb" by Steve Sheinkin

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.