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neutron

[noo-tron, nyoo-]
noun Physics.
  1. an elementary particle having no charge, mass slightly greater than that of a proton, and spin of ½: a constituent of the nuclei of all atoms except those of hydrogen. Symbol: n
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Origin of neutron

First recorded in 1920–25; neutr(o)- + -on1
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for neutron

Contemporary Examples

Historical Examples

  • The same thing goes for a proton or electron or neutron or even a neutrino.

    By Proxy

    Gordon Randall Garrett

  • These units are the positron, the negatron, and the neutron.

    Cube Root of Conquest

    Roger Phillips Graham

  • The actual limit is when the star has reached the density of a neutron, and this star hasn't collapsed that far by a long shot.

    Islands of Space

    John W Campbell

  • The Miran answered with the neutron beam, atomic and gamma bombs—and the crumbler ray.

    The Ultimate Weapon

    John Wood Campbell

  • Heat—quantities of heat were being poured into the little ship, and the neutron guns were doing their best to add to it.

    The Ultimate Weapon

    John Wood Campbell

British Dictionary definitions for neutron

neutron

noun
  1. physics a neutral elementary particle with a rest mass of 1.674 92716 × 10 –27 kilogram and spin 1/2; classified as a baryon. In the nucleus of an atom it is stable, but when free it decays
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Word Origin

C20: from neutral, on the model of electron
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

Word Origin and History for neutron

n.

"electrically neuter particle of the atom," 1921, coined by U.S. chemist William D. Harkins (1873-1951) from neutral (adj.) + -on. First record of neutron bomb is from 1960. Neutron star attested from 1934, originally hypothetical; so called because it would be composed of neutrons.

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Online Etymology Dictionary, © 2010 Douglas Harper
neutron in Medicine

neutron

(nōō′trŏn′)
n.
  1. An electrically neutral subatomic particle in the baryon family, having a mass 1,839 times that of the electron, stable when bound in an atomic nucleus, and having a mean lifetime of approximately 1.0X103 seconds as a free particle. It and the proton form nearly the entire mass of atomic nuclei.
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The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
neutron in Science

neutron

[nōō′trŏn′]
  1. An electrically neutral subatomic particle in the baryon family, having a mass of 1.674 X 10-24 grams (1,838 times that of the electron and slightly greater than that of the proton). Neutrons are part of the nucleus of all atoms, except hydrogen, and have a mean lifetime of approximately 1.0X103 seconds as free particles. They consist of a triplet of quarks, including two down quarks and one up quark, bound together by gluons. In radioactive atoms, excess neutrons are converted to protons by beta decay. Beams of neutrons from nuclear reactors are used to bombard the atoms of various elements to produce fission and other nuclear reactions and to determine the atomic arrangements in molecules. See Table at subatomic particle.
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The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
neutron in Culture

neutron

An elementary particle without an electrical charge; one of the building blocks of the nucleus of the atom. A neutron has about the same mass as a proton.

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The New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.