Definition of neutrino in US English:



  • A neutral subatomic particle with a mass close to zero and half-integral spin, rarely reacting with normal matter. Three kinds of neutrinos are known, associated with the electron, muon, and tau particle.

    • ‘The proton and the neutron are baryons; the electron, the muon, and the neutrino are leptons; whilst the pions are mesons.’
    • ‘And if we hit a proton with an electron, we get a neutron and an electron neutrino at the other end.’
    • ‘The leptons consist of the charged electron, muon and tau, together with three electronically neutral particles - the electron neutrino, muon neutrinos and tau neutrinos.’
    • ‘The electron and muon neutrinos are easier to produce and detect than the tau neutrino.’
    • ‘Cosmic neutrinos are extremely high energy subatomic particles, like protons and electrons, but neutrinos have no electrical charge.’


1930s: from Italian, diminutive of neutro ‘neutral’.