fissile, a.
(ˈfɪsɪl, now usu. ˈfɪsaɪl)
Also 7 fissel, 8 fissil.
[ad. L. fissil-is, f. findĕre to cleave: see -ile. Cf. Fr. fissile.]
1. Capable of being divided or split; cleavable; inclined or tending to split.
| 1661 Lovell Hist. Anim. & Min. Introd., Some are Fissil, as the spectacle stone; others not, as mettals. 1756 C. Lucas Ess. Waters II. 128 It springs slowly through a soft, fissil rock. 1830 Lyell Princ. Geol. (1875) II. iii. xlviii. 572 Layers of drift peat, sand or fissile clay. 1857 H. Miller Test. Rocks xi. 427 They communicate often a fissile character to the stone in which they occur. 1887 Bowen Virg. æneid vi. 180 Ash-hewn timbers and fissile oaks with the wedges are rent. |
2. spec. in Nuclear Physics. Capable of undergoing nuclear fission; sometimes used specifically of materials capable of fission upon absorption of a slow (as opposed to a fast) neutron.
| 1945 Nature 29 Dec. 768/1 The first bomb had not been dropped but..large production plants were rapidly accumulating the fissile material which it was planned to use. 1950 [see fissionable a.]. 1950 J. Cockcroft in Crammer & Peierls Atomic Energy iv. 75 Fast reactors require considerable quantities of scarce fissile material such as U 235. 1953 Economist 14 Nov. 508/1 These [‘breeder’ reactor] plants, which create fissile fuel out of normally non-fissile materials at a faster rate than they are used up, are in the early stage of development. 1957 Observer 7 July 11/8 The ‘gaseous diffusion’ process used during the war to separate fissile uranium-235 for atomic bombs from natural uranium was based on this work [of Professor S. Chapman]. 1958 Listener 19 June 1005/1 There are fissile materials (such as plutonium, and uranium-235) which can undergo nuclear chain-reactions. 1965 [see fission v. 2]. |
Hence ˈfissileness = next.
| 1727 Bailey vol. II, Fissileness, aptness to be cleaved. |