I. ˈfishən also -izh- noun
( -s )
Etymology: Latin fission-, fissio, from fissus (past participle of findere to split) + -ion-, -io -ion — more at bite
1. : the process or an instance of cleaving, splitting, or breaking up into parts
cites the fission of many families during the civil strife — Boyd Keenan
our diplomacy will have to be resourceful … to avert disastrous fissions in the free world during the next few weeks — E.K.Lindley
2. : reproduction by spontaneous division of the body into two or more parts each of which grows into a complete organism, being the common mode of reproduction among the bacteria, fission algae, and protozoa — see binary fission , multiple fission
3. : cleavage 5
4. : the splitting of an atomic nucleus (as by bombardment with neutrons) especially into approximately equal parts resulting in the release of enormous quantities of energy when certain heavy elements (as uranium and plutonium) are split — called also nuclear fission ; contrasted with fusion ; distinguished from spallation
II. verb
( fissioned ; fissioned ; fissioning -sh(ə)niŋ, -zh(- ; fissions )
transitive verb
: to cause to undergo fission
an element fissioned by high energy particles
intransitive verb
: to undergo fission
the number of free atoms released when a U-235 atom fissions — Scientific American