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fission of a uranium nucleus


 (fĭsh′ən, fĭzh′-)
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
References in periodicals archive ?
Interestingly, the two larger elements of the fissioned chromosome 1 found in the FM2 cytotype are not truly telocentric but possess minute short arms (subacrocentric).
Significant deviation from the expected equal ratio of inverted to noninverted and fissioned to nonfissioned chromosomes was detected in one of the fission/inv(4) heterozygotes (BYU 39833).
The first two types of termination would produce terminal taxa with primarily fissioned chromosomal complements or which are heteromorphic for the final rearrangements of the series, and in which the heteromorphisms are meiotically neutral or nearly so.