neutron (n.)youdaoicibaDictYouDict[neutron 词源字典]
"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.[neutron etymology, neutron origin, 英语词源]