https://doi.org/10.1351/goldbook.F02394
  1. (of a @N04257@) Capable of undergoing @N04229@ by interaction with (slow) neutrons.
  2. (of a material) Containing one or more fissile nuclides.
Source:
PAC, 1982, 54, 1533. (Glossary of terms used in nuclear analytical chemistry (Provisional)) on page 1542 [Terms] [Paper]