From AMS Glossary
An uncharged subatomic particle.
The rest mass of the neutron is slightly greater than that of the proton. Atomic nuclei are composed of protons and neutrons bound together by nuclear forces. The common term for neutron or proton is nucleon. Although the neutron is electrically neutral it does possess a charge structure and a magnetic dipole moment. The existence of the neutron was first demonstrated by James Chadwick in 1932.
Boorse, H. A., and L. Motz 1966. The World of the Atom. Vol. II, . 1288–1308.