fis·​sile | \ ˈfi-səl How to pronounce fissile (audio) , ˈfi-ˌsī(-ə)l\

Definition of fissile

1 : capable of or prone to being split or divided in the direction of the grain or along natural planes of cleavage fissile wood fissile crystals
2 : capable of undergoing fission

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Other Words from fissile

fissility \ fi-​ˈsi-​lə-​tē How to pronounce fissility (audio) \ noun

Did You Know?

When scientists first used fissile back in the 1600s, the notion of splitting the nucleus of an atom would have seemed far-fetched indeed. In those days, people thought that atoms were the smallest particles of matter that existed and therefore could not be split. Fissile (which can be traced back to Latin findere, meaning "to split") was used in reference to things like rocks. When we hear about "fissile materials" today, the reference is usually to nuclear fission: the splitting of an atomic nucleus that releases a huge amount of energy. But there is still a place in our language for the original sense of fissile (and for the noun fissility, meaning "the quality of being fissile"). A geologist, for example, might refer to slate as being fissile.

Examples of fissile in a Sentence

Recent Examples on the Web

The aging facility about 60 miles north of Pyongyang was once the main source of its fissile material, turning out roughly enough plutonium each year for one atomic bomb. Jon Herskovitz, Fortune, "Why the Trump-Kim Nuclear Show Is Set for Act Three," 20 June 2019 While negotiations stalled, North Korea is believed to have continued to produce fissile materials., "It was the eighth time North Korea has tested ballistic missiles or other projectiles since late July, and the first weapons test in 17 days.," 11 Sep. 2019 Under the agreement, Iran is allowed limited research and development on advanced centrifuges, which accelerate the production of fissile material that can be used to make a nuclear bomb. Erin Cunningham, Washington Post, "Iran now operating advanced centrifuges in breach of nuclear pact," 9 Sep. 2019 Under the agreement, Iran is allowed limited research and development on advanced centrifuges, which accelerate the production of fissile material that can be used to make a nuclear bomb. Erin Cunningham, Anchorage Daily News, "Iran now operating advanced centrifuges in breach of nuclear pact that US rejected," 7 Sep. 2019 Amid the fissile atmosphere in the Gulf and the Strait of Hormuz, a single mistake could unleash catastrophe. Sam Kiley, CNN, "On the ship that downed a military drone, one small mistake could cause a war with Iran," 19 July 2019 When there are enough fissile atoms close together — a quantity known as critical mass — the particles ejected by fission can strike other fissile atoms, triggering more atoms to split apart and so on. Umair Irfan, Vox, "Uranium enrichment will be a key point in talks with North Korea. Here’s what it is.," 11 June 2018 Kim’s arsenal of 30 to 60 nuclear warheads remains and more fissile material is being produced daily. Trudy Rubin, The Mercury News, "Rubin: Trump’s meeting with Kim Jong Un isn’t producing results," 8 July 2019 North Korea has continued to churn out fissile material and is no longer an isolated pariah on the world stage. Washington Post, "AP Analysis: Trump smiles with North Korea, threatens Iran," 2 July 2019

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'fissile.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of fissile

1661, in the meaning defined at sense 1

History and Etymology for fissile

borrowed from Latin fissilis "easily split," from fid-, variant stem of findere "to split, cleave" + -tilis "subject to, susceptible to (the action of the verb)" — more at bite entry 1

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Last Updated

4 Oct 2019

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Time Traveler for fissile

The first known use of fissile was in 1661

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Rhyming Dictionary: Words that rhyme with fissile

Nglish: Translation of fissile for Spanish Speakers

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