capable of or prone to being split or divided in the direction of the grain or along natural planes of cleavage.
capable of being split or divided; cleavable
possessing a nucleus able to undergo fission
(of a nuclide) able to undergo fission induced by low-energy neutrons, as uranium 233
describes materials that are capable of undergoing fissionthat is, the process in which the nucleus of a heavy atom is split apart, releasing a large amount of energy.