Dictionary.com
Thesaurus.com

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.


fissile British  
/ ˈfɪsaɪl /

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

"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

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.

See Examples For:

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

Those are the stockpiles of fissile material and the deep-underground Pickaxe Mountain site that could in time be used to enrich it to weapons-grade.

From The Wall Street Journal Mar. 26, 2026

Pyongyang is now estimated to possess up to 50 nuclear warheads and enough fissile material to produce up to 40 more, according to the Stockholm International Peace Research Institute, a think tank.

From The Wall Street Journal Mar. 4, 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

Vocabulary.com logo
by dictionary.com

Dictionary.com's Learning Companion

Go beyond just looking up words.
Remember them forever with VocabTrainer.

Start training