fissile

American  

[fis-uhl] / ˈfɪs əl /

adjective

1. capable of being split or divided; cleavable.

2. Physics.

   1. fissionable.

   2. (of a nuclide) capable of undergoing fission induced by low-energy neutrons, as uranium 233 and 235.

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fissile British  

/ ˈfɪsaɪl, fɪˈsɪlɪtɪ /

adjective

1. capable of undergoing nuclear fission as a result of the impact of slow neutrons

2. another word for fissionable

3. tending to split or capable of being split

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Other Word Forms

• fissility noun
• nonfissile adjective
• nonfissility noun
• unfissile adjective

Etymology

Origin of fissile

1655–65; < Latin fissilis, equivalent to fiss ( us ) ( see fissi-) + -ilis -ile

Example Sentences

Both Leavitt and Hegseth, however, mentioned that the United States wants to ensure Iran does not have stockpiles of enriched uranium, the fissile material that is key in developing nuclear weapons.

From Los Angeles Times • Apr. 8, 2026

The Kim regime has an estimated stockpile of roughly 50 nuclear warheads, with the fissile material to produce dozens more.

From The Wall Street Journal • Mar. 15, 2026

Its magic trick is that 0.7% of the element found in nature is fissile.

From Barron's • Dec. 26, 2025

It is unclear when Mr Kim made the visit and if the site is at the North's sprawling Yongbyon nuclear complex, which produces fissile material for Pyongyang's nuclear weapons.

From BBC • Sep. 13, 2024

From the slugs of irradiated uranium, fissile plutonium would be extracted at a second plant ten miles away, eventually to be sent on its way to Los Alamos.

From "Big Science" by Michael Hiltzik