Any material readily fissioned by slow neutrons, for example, uranium 235 and plutonium 239.
Material whose atoms are easily split when struck by neutrons, and that can easily sustain either a controlled or explosive chain reaction, depending on concentration and other conditions of use; also commonly referred to as a "fissile" material.
A material that can be fissioned (split) into other nuclei by any process.
Material that can undergo nuclear fission when bombarded by a high-energy neutron. Most fissionable materials that are not fissile cannot sustain chain reactions.
A substance whose atoms can be split by slow neutrons. Uranium–235, plutonium–239 and uranium–233 are fissionable materials.
Commonly used as a synonym for fissile material, the meaning of this term has been extended to include material that can be fissioned by fast neutrons, such as uranium-238.
A material whose nuclei can be induced to fission by a neutron.