noun, plural lep·ta [lep-tuh] /ˈlɛp tə/.
- an aluminum coin of modern Greece until the euro was adopted, the 100th part of a drachma.
- a small copper or bronze coin of ancient Greece.
- 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.
noun plural -ta (-tə)
- a former Greek monetary unit worth one hundredth of a drachma
- a small coin of ancient Greece
- physics any of a group of elementary particles and their antiparticles, such as an electron, muon, or neutrino, that participate in electromagnetic and weak interactions and have a half-integral spin
n.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 n.
- Any of a family of elementary particles that participate in the weak interaction, including the electron and its associated neutrino.
- 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.
Any one of six elementary particles that are one of the fundamental constituents of matter. Leptons are not affected by the strong force and are not normally found in the nucleus of the atom. The electron and the neutrino are examples of leptons.