Any of a group of subatomic particles having odd half-integral spin (, ). Fermions are named for the Fermi-Dirac statistics that describe their behaviour. They include particles in the class of leptons, baryons, and nuclei of odd mass number (e.g., tritium, helium-3, uranium-233). They obey the Pauli exclusion principle. Fermions are produced and undergo annihilation in particle-antiparticle pairs. See also boson.

This entry comes from Encyclopædia Britannica Concise.
For the full entry on fermion, visit Britannica.com.

Seen & Heard

What made you look up fermion? Please tell us what you were reading, watching or discussing that led you here.

Get Our Free Apps
Voice Search, Favorites,
Word of the Day, and More
Join Us on FB & Twitter
Get the Word of the Day and More