fis·sion /ˈfɪʃṇ, ʒṇ/
fis·sion /ˈfɪʃən , ˈfɪʒ-/ 名詞
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.
n 1: a nuclear reaction in which a massive nucleus splits into
smaller nuclei with the simultaneous release of energy
[syn: nuclear fission]
2: reproduction of some unicellular organisms by division of
the cell into two more or less equal parts