fissive,a.|ˈfɪsɪv| [f. L. type *fissīvus, f.findĕre (pa.pple.fissus) to split.] Pertaining to, or of the nature of, fission. 1875Huxley & Martin Elem.Biol. v. 29 The whole plant is built up by the fissive multiplication of the simple cell in which it takes its origin.