1715–25; < Greekleptón (nómisma) a small (coin), noun use of neuter of leptós small; see lepto-
Definition for lepton (2 of 2)
[ lep-ton ]
/ ˈlɛp tɒn /
any of a class of particles with spin of ½ that are not subject to the strong force and that are believed to be truly elementary and not composed of quarks or other subunits. The leptons known or believed to exist are the electron and electron-neutrino, the muon and mu-neutrino, and the tau lepton and tau-neutrino.
elementary particle of small mass, 1948, from Greek leptos "small, slight, slender, delicate" (from lepein "to peel," from PIE *lep-; see leper) + -on. Also the name of a small coin in ancient Greece, from neuter of leptos
Any of a family of elementary particles that interact through the weak force and do not participate in the strong force. Leptons include electrons, muons, tau particles, and their respective neutrinos, the electron neutrino, the muon neutrino, and the tau neutrino. The antiparticles of these six particles are also leptons. Compare hadron. See Note at elementary particle. See Table at subatomic particle.