'fissionable' definitions:

Definition of 'fissionable'

From: WordNet
adjective
Capable of undergoing nuclear fission; "a fissionable nucleous"; "fissionable material" [syn: fissionable, fissile] [ant: nonfissionable]

Definition of 'fissionable'

From: GCIDE
  • fissionable \fis"sion*able\, a. Capable of undergoing nuclear fission; -- a property of certain isotopes of elements with heavy nuclei.
  • Syn: fissile. [PJC]