noun. ['ˈnuːˌtrɑːn'] an elementary particle with 0 charge and mass about equal to a proton; enters into the structure of the atomic nucleus.
1. Noun, singular or mass No one had ever observed a neutron or proven that it existed, though. 2. Adjective Gadolinium is a silvery-white, highly ductile rare earth metal used as a neutron absorber in nuclear reactors.
