FISSILE
fissile
(adjective) capable of being split or cleft or divided in the direction of the grain; “fissile crystals”; “fissile wood”
fissionable, fissile
(adjective) capable of undergoing nuclear fission; “a fissionable nucleous”; “fissionable material”
Source: WordNet® 3.1
Etymology
Adjective
fissile (comparative more fissile, superlative most fissile)
Able to be split
(geology) Easily split along a grain
(physics) Capable of undergoing nuclear fission, especially by collision with a thermal neutron
Source: Wiktionary
Fis"sile, a. Etym: [L. fissilis, fr. fissus, p.p. of findere to
split. See Fissure.]
Definition: Capable of being split, cleft, or divided in the direction of
the grain, like wood, or along natural planes of cleavage, like
crystals.
This crystal is a pellucid, fissile stone. Sir I. Newton.
Source: Webster’s Unabridged Dictionary 1913 Edition