nucleon

n. proton or neutron as a component of a nucleus (Physics)

This article is about the real-life sub-atomic particles. For the fictional power source used in the Transformers Universes, see Nucleon (Transformers). For the Ford concept car, see Ford Nucleon. In physics a nucleon is a collective name for two baryons: the neutron and the proton. They are constituents of the atomic nucleus and until the 1960s were thought to be elementary particles. In those days their interactions (now called internucleon interactions) defined strong interactions. Now they are known to be composite particles, made of quarks and gluons. Understanding the nucleons' properties is one of the major goals of quantum chromodynamics, the modern theory of strong interactions.
See more at Wikipedia.org...

Noun
1. a constituent (proton or neutron) of an atomic nucleus
(hypernym) baryon, heavy particle
(hyponym) antineutron
(part-holonym) nucleus

n. nucleon, proton or neutron as a component of a nucleus (Physics)

Common name for a constituent particle of the atomic nucleus. At present, applied to protons and neutrons, but may include any other particles found to exist in the nucleus.