fissile
Americanadjective
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capable of being split or divided; cleavable.
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Physics.
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(of a nuclide) capable of undergoing fission induced by low-energy neutrons, as uranium 233 and 235.
adjective
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capable of undergoing nuclear fission as a result of the impact of slow neutrons
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another word for fissionable
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tending to split or capable of being split
Other Word Forms
Etymology
Origin of fissile
1655–65; < Latin fissilis, equivalent to fiss ( us ) ( see fissi-) + -ilis -ile
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.
But the fissile material required to build nuclear weapons remains in the country, under the watch of U.S. satellite surveillance.
From Los Angeles Times ● Jul. 21, 2026
North Korea currently has an estimated 60 nuclear warheads, plus enough fissile material to make at least 90 more, according to a new estimate by the Stockholm International Peace Research Institute.
From The Wall Street Journal ● Jun. 10, 2026
The Comprehensive Nuclear Test Ban Treaty of 1996 allows activities to assure the safety and reliability of nuclear weapons, including experiments involving fissile material, as long as they don’t result in a nuclear-explosive yield.
From The Wall Street Journal ● Feb. 6, 2026
Its magic trick is that 0.7% of the element found in nature is fissile.
From Barron's ● Dec. 26, 2025
The discovery of a fissile isotope that could be separated from its parent by chemical means might quell the skepticism still bogging down the uranium program.
From "Big Science" by Michael Hiltzik
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.
