Definition of positron in US English:



  • A subatomic particle with the same mass as an electron and a numerically equal but positive charge.

    • ‘The decaying atoms emit positrons, which encounter electrons and are annihilated, releasing pairs of gamma rays.’
    • ‘Electrons, positrons, and photons can be separated and isolated at macroscopic distances.’
    • ‘The full scattering amplitude is the sum of all contributions from all possible loops of photons, electrons, positrons, and other available particles.’
    • ‘So the normally stable proton can decay into a neutron, a positron, and a neutrino if continuously fed enough energy through constant, extreme acceleration.’
    • ‘The term accelerators most commonly refers to particle accelerators, devices for increasing the velocity of subatomic particles such as protons, electrons, and positrons.’


1930s: from positive + -tron.