- 1. The act of splitting, e.g., amitotic division of a cell or its nucleus. 2. Splitting of the nucleus of an atom. [L. fissio, a cleaving, fr. findo, pp. fissus, to cleave]- bud f. SYN: gemmation.- multiple f. division of the nucleus, simultaneously or successively, into a number of daughter nuclei, followed by division of the cell body into an equal number of parts, each containing a nucleus.
* * *fis·sion 'fish-ənalso 'fizh- n1) a method of reproduction in which a living cell or body divides into two or more parts each of which grows into a whole new individual2 a) CLEAVAGE (2)b) the splitting of an atomic nucleus resulting in the release of large amounts of energy called also nuclear fissionfis·sion vb, fis·sioned; fis·sion·ing 'fish-(ə-)niŋalso 'fizh-fis·sion·al 'fish-ən-əlalso 'fizh- adj
* * *n.a method of asexual reproduction in which the body of a protozoan or bacterium splits into two equal parts (binary fission), as in the amoeba, or more than two equal parts (multiple fission), for example sporozoite formation in the malarial parasite (see Plasmodium). The resulting products of fission eventually grow into complete organisms.
* * *fis·sion (fishґən) [L. fissio] 1. the act of splitting. 2. a form of asexual reproduction in which the cell divides into two or more daughter parts of equal size, each of which becomes a new, independent organism; it is seen chiefly in unicellular organisms such as bacteria. See also binary f. and multiple f.
Medical dictionary. 2011.