nucleon

a constituent (proton or neutron) of an atomic nucleus

• antineutron — the antiparticle of a neutron
• antiproton — an unstable negatively charged proton; the antiparticle of a proton
• neutron — an elementary particle with 0 charge and mass about equal to a proton; enters into the structure of the atomic nucleus
• proton — a stable particle with positive charge equal to the negative charge of an electron

• baryon, heavy particle — any of the elementary particles having a mass equal to or greater than that of a proton and that participate in strong interactions; a hadron with a baryon number of +1

• nucleus — the positively charged dense center of an atom