• synonyms


[fis-uh l]
  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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Origin of fissile

1655–65; < Latin fissilis, equivalent to fiss(us) (see fissi-) + -ilis -ile
Related formsfis·sil·i·ty, nounnon·fis·sile, adjectivenon·fis·sil·i·ty, nounun·fis·sile, adjective
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

British Dictionary definitions for non-fissile


  1. British capable of undergoing nuclear fission as a result of the impact of slow neutrons
  2. US and Canadian another word for fissionable
  3. tending to split or capable of being split
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Derived Formsfissility (fɪˈsɪlɪtɪ), noun

Word Origin

C17: from Latin fissilis, from fissus split; see fissi-
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

Word Origin and History for non-fissile



1660s, from Latin fissilis "that which may be cleft or split," from fissus, past participle of findere (see fissure).

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Online Etymology Dictionary, © 2010 Douglas Harper