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fission of a uranium nucleus
1. The act or process of splitting into parts.
2. A nuclear reaction in which an atomic nucleus, especially a heavy nucleus, such as an isotope of uranium, splits into fragments, usually two fragments of comparable but unequal mass, and releases a few neutrons and about 100 million electron volts of energy. Nuclear fission may occur spontaneously or may be induced by the absorption of a neutron, which can initiate a nuclear chain reaction.
3. Biology An asexual reproductive process in which a unicellular organism divides into two or more independently maturing daughter cells.
v. fis·sioned, fis·sion·ing, fis·sions
To cause (an atom) to undergo fission.
To undergo fission.
[Latin fissiō, fissiōn-, a cleaving, from fissus, split; see fissi-.]
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
split or broken into parts
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014