- a neutron produced by nuclear fission that has lost little energy by collision; a neutron with a kinetic energy in excess of 0.1 MeV
- a neutron with a kinetic energy in excess of 1.5 MeV, the fission threshold of uranium-238
Gearhead Slang For The Fast LaneRead more in this article about some frequently asked questions and fun facts related to our definitions.
Where Did The Phrase “Fast And The Furious” Come From?The continued box office success of the Fast and the Furious franchise gives moviegoers and word-lovers something to cheer about. Beyond the stunning action sequences, though, audiences, including us, actually really enjoy the title itself.
- fast food,
- fast forward,
- fast ice,
- fast lane,
- fast motion,
- fast of gedaliah,
- fast one,
- fast reactor,
- fast rhythm,
- fast smear
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
A neutron that is not in thermal equilibrium with the surrounding medium, especially one produced by fission. Compare slow neutron. See also fast-breeder reactor.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.