fission Meaning, Definition & Usage
- 
       noun reproduction of some unicellular organisms by division of the cell into two more or less equal parts
        
      
 
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       noun a nuclear reaction in which a massive nucleus splits into smaller nuclei with the simultaneous release of energy
       
       
 nuclear fission.
 
WordNet
Fis"sion noun
Etymology
L.Definitions
-  A cleaving, splitting, or breaking up into parts. 
-  (Biol.) A method of asexual reproduction among the lowest (unicellular) organisms by means of a process of self-division, consisting of gradual division or cleavage of the into two parts, each of which then becomes a separate and independent organisms; as when a cell in an animal or plant, or its germ, undergoes a spontaneous division, and the parts again subdivide. See Segmentation , and Cell division, underDivision .
-  (Zoöl.) A process by which certain coral polyps, echinoderms, annelids, etc., spontaneously subdivide, each individual thus forming two or more new ones. See Strobilation .