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, which releases a large number of lethal neutrons but produces little blast, is from 1960. Neutron star attested from 1934, originally hypothetical; so called because it would be composed of densely packed neutrons.