"A small thing. Doesn't have an electrical charge." -ICantEdit
Neutrons are a kind of nucleon that contain one up quark and two down quarks, and these quarks are held together by gluons. Neutrons are almost always found within atoms, and they have no charge, or a 'neutral' charge and they are called 'neutrons'. The other kind of nucleon, called a proton, are usually found near them as well. Both protons and neutrons make up the atomic nucleus.