Any of a class of fundamental particles that consists of the electron, muon, tau particle and three types of neutrino. For each lepton there is an equivalent antiparticle.
The antileptons have a charge opposite that of the leptons; the antineutrinos, like the neutrinos, have no charge. The electron, muon and tau all have a charge of -1. These three particles differ from each other only in mass: the muon is 200 times more massive than the electron and the tau is 3500 times more massive than the electron. Leptons interact by the electromagnetic interaction and the weak interaction.