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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.

In 1943 the Quebec Agreement formalized a collaboration between British and American scientists who would build the atomic bomb.

From The Wall Street Journal • Mar. 23, 2026

One of them in Nagasaki survived the 1945 atomic bomb blast and is still in working order, 117 years after it was fabricated and shipped from Scotland.

From BBC • Feb. 16, 2026

America built the atomic bomb when the physics seemed impossible.

From The Wall Street Journal • Dec. 1, 2025

The project, code named Divider, was the 1,054th nuclear weapons test conducted by the US, according to the Los Alamos National Laboratory, which played a central role in helping develop the world's first atomic bomb.

From BBC • Oct. 29, 2025

While they had dinner, Fuchs told Gold that the atomic bomb was being designed at a place called Los Alamos.

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.