In physics, a hadron is a subatomic particle composed of quarks and gluons.

The class of hadrons is further subdivided into three subclasses.

  • Baryons, formed by three quarks, like protons and neutrons
  • 'Exotic Baryons', including the pentaquark, a particle of five quarks
  • Mesons, formed by configurations quark/antiquark pairs, such as pions and kaons.