An Etymological Dictionary of Astronomy and Astrophysics

An → elementary particle that does not participate in the → strong interaction. The Lepton family
includes → electrons, → muons, tau leptons, → neutrinos and their → antiparticles. The lepton is a
→ fermion.

See also: From Gk, lepto-, combining form of leptos “small, slight” + -on a suffix used in the names of subatomic particles (gluon; meson; neutron), quanta (photon; graviton), and other minimal entities or components.