Fis"sion (?), n. [L. fissio. See Fissure.]
1.
A cleaving, splitting, or breaking up into parts.
2. 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, under Division.
3. Zool.
A process by which certain coral polyps, echinoderms, annelids, etc., spontaneously subdivide, each individual thus forming two or more new ones. See Strobilation.
© Webster 1913.