Definition of photon in English:


Line breaks: pho¦ton
Pronunciation: /ˈfəʊtɒn


  • A particle representing a quantum of light or other electromagnetic radiation. A photon carries energy proportional to the radiation frequency but has zero rest mass.
    More example sentences
    • The world of the realist is populated by electrons and photons, quarks and gluons.
    • Until now, physicists have only been able to entangle photons, electrons and atoms, using different methods in each case.
    • A photon has zero rest mass, but it carries energy and momentum.



More example sentences
  • Along with Tapp, he is also developing a scanner for measuring body composition that combines induction tomography with an optical imaging technique called photonic scanning.
  • Laser or photonic engines, because they might be propelled by laser beams inflating a gigantic sail, may have even larger specific impulses.
  • Such band gaps are the photonic analogue of the electronic band gaps displayed by conventional crystals, but here they prevent photons - rather than electrons - from propagating.


early 20th century: from Greek phōs, phōt- 'light', on the pattern of electron.

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