photon
noun
\
Definition of photon
1 : a quantum of electromagnetic radiation Should a substance happen to have a lot of electrons in a higher level, and a lower level is mostly empty …, then a photon can cause an electron to transfer from a higher state to a lower one. This change releases energy and creates a new photon, in addition to the one which caused the transfer. This photon can in turn induce more electrons to fall to a lower state.— Robert Gilmore
2 dated : troland
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Other Words from photon
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adjective
Examples of photon in a Sentence
Recent Examples on the Web
According to the standard model, hydrogen and antihydrogen ought to have the exact same states and absorb photons of the exact same energies. — Adrian Cho, Science | AAAS, "Atoms and antiatoms haven’t crashed Albert Einstein’s theory of relativity—yet," 4 Apr. 2018 These photons started out with short radio wavelengths, but over their more than 13-billion-year journey to Earth, the universe's expansion stretched them out to long wavelengths, or low megahertz frequencies. — Daniel Clery, Science | AAAS, "China’s moon mission will probe cosmic dark ages," 16 May 2018 In fact, neutrinos are the second most ubiquitous particles, second only to the cosmic microwave background photons left over from the Big Bang. — Smithsonian, "Scientists Explain The Thrill of Detecting a Neutrino From a Far-Off Galaxy," 12 July 2018 The defects can take and store quantum information in the form of electrons for relatively long periods of time and link it efficiently to photons. — Fox News, "Scientists are using diamonds to send secret messages," 6 July 2018 Just like a photon of light behaves like both a particle and a wave, this blob also has wavelike properties, where one part can actually interfere with another part, to produce ripples in itself like waves colliding in a pond. — Sophia Chen, WIRED, "The Quest to Make Super Cold Quantum Blobs in Space," 25 June 2018 High-energy light from distant sources rarely makes it to Earth, because photons are so reactive they get lost along the way. — Author: Sarah Kaplan, Anchorage Daily News, "In a cosmic first, scientists detect ‘ghost particles’ from a distant galaxy," 12 July 2018 High-energy light from distant sources rarely makes it to Earth, because photons are so reactive they get lost along the way. — Sarah Kaplan, chicagotribune.com, "In a cosmic first, scientists detect 'ghost particles' from a distant galaxy," 12 July 2018 Both were designed to catch photons from planets around other stars, unlike most techniques for studying exoplanets that rely on more indirect signatures. — Joshua Sokol, WIRED, "These Spinning Disks of Gas and Dust Reveal How Planets Get Made," 28 May 2018These example sentences are selected automatically from various online news sources to reflect current usage of the word 'photon.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.
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More Definitions for photon
photon
noun
English Language Learners Definition of photon
physics : a tiny particle of light or electromagnetic radiation
See the full definition for photon in the English Language Learners Dictionary
photon
noun
\
Medical Definition of photon
1
: a unit of intensity of light at the retina equal to the illumination received per square millimeter of a pupillary area from a surface having a brightness of one candela per square meter
— called also
troland
2 : a quantum of electromagnetic radiation
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