/ Dictionary / Index N neutron: Meaning and Definition of Find definitions for: neu•tron Pronunciation: (n'tron, ny'-), [key] — n. Physics. an elementary particle having no charge, mass slightly greater than that of a proton, and spin of : a constituent of the nuclei of all atoms except those of hydrogen. Symbol: n Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: neutron (Thesaurus) neutro- neutron activation analysis Related Content Daily Word Quiz: agitated Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language