fermions

Noun

fermion (plural fermions)

1. (particle, Standard Model) Any elementary or composite particle that has half-integer spin and thus obeys Fermi–Dirac statistics and the Pauli exclusion principle (equivalently, a particle for which the wavefunction of any system of identical such particles changes sign whenever two are swapped); a baryon, a lepton or a quark;
   • The fermions treated by the Standard Model are the (composite) baryons and the (elementary) leptons and quarks.
2. (particle, Standard Model, slightly more loosely) any such particle or any composite particle composed of fermions.