an elementary particle with 0 charge and mass about equal to a proton; enters into the structure of the atomic nucleus
"The neutron, an uncharged particle with mass nearly identical to that of a proton, resides within the atom's nucleus."
A subatomic particle forming part of the nucleus of an atom and having no charge; it is a combination of an up quark and two down quarks.
"A neutron is a neutral subatomic particle found in the atomic nucleus, composed of one up quark and two down quarks."
In plain English: A neutron is an electrically neutral particle found inside the nucleus of every atom along with protons.
"Scientists use neutrons to study how atomic nuclei hold together without breaking apart."
The word neutron comes from combining neutral with the suffix -on. It was coined in 1899 by physicist William Sutherland before gaining its modern meaning alongside "proton" in 1920.