Did you know?
When scientists first used fissile back in the 1600s, the notion of splitting an atom would have seemed far-fetched indeed. At that time, 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 the Latin verb 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 or builder, for example, might describe slate as being fissile, as it splits readily into thin slabs.
Examples of fissile in a Sentence
Ana Ceballos, Los Angeles Times, 14 June 2026
The enrichment process Gas centrifuge enrichment works by spinning uranium hexafluoride gas at high speed; the heavier uranium-238 isotope migrates toward the outer wall while the lighter, fissile uranium-235 concentrates near the axis.
—Aditya Jadhav, Interesting Engineering, 11 June 2026
Part of that perception stemmed from Iran's rapid manufacture of centrifuges, which are needed to produce the fissile material that could be used in nuclear bombs, in the 2000s.
—Kevin Breuninger, CNBC, 6 June 2026
There’s still fissile material, highly enriched, that was not there at the beginning of his first term.
—NBC news, 10 May 2026
See All Example Sentences for fissile
Cite this Entry
“Fissile.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/fissile. Accessed 21 Jun. 2026.
Copy Citation
