photon

noun
pho·​ton | \ ˈfō-ˌtän \

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

photonic \ fō-​ˈtä-​nik \ adjective

Science and the Photon

It was Albert Einstein who first theorized that the energy in a light beam exists in small bits or particles, and scientists today know that light sometimes behaves like a wave (somewhat like sound or water) and sometimes like a stream of particles. The energies of photons range from high-energy gamma rays and X-rays down to low-energy infrared and radio waves, though all travel at the same speed. The amazing power of lasers is the result of a concentration of photons that have been made to travel together in order to hit their target at the same time.

Examples of photon in a Sentence

Recent Examples on the Web

Then there are the force carriers: photons, W and Z bosons, the Higgs, and gluons. Chris Lee, Ars Technica, "Quark-gluon plasma reveals viscosity-free properties," 19 Dec. 2018 Using a two-photon laser, the scientists created a set of sperm harnesses—tiny tubes with flexible arms that cling to the head. Megan Molteni, WIRED, "Spermbots Offer a Promising New Way to Target Cancer," 17 May 2018 In other words, the ratio of baryons, which include protons and neutrons, to photons, which light is made of, would have to shrink. Charles Q. Choi, Space.com, "Why Alternate Universes Might Also Host Life Around their Stars," 26 Sep. 2018 Earlier this year, physicists discovered that photons are actually able to send messages to themselves. David Grossman, Popular Mechanics, "Scientists Get Nanoparticles Spinning a Billion Times Per Second," 19 July 2018 No doubt Carol and her super strength and photon beams will be an asset against the biggest and baddest villain in the Marvel Universe. Alex Abad-santos, Vox, "Captain Marvel and the future of the Avengers, explained," 18 Sep. 2018 The difference between an economy that sorts the information and energy in photons and one that sorts the information and energy in dollars is a slight one in my mind. Jesse Jarnow, WIRED, "The Ghost of John Perry Barlow Lives in His Posthumous Memoir," 5 June 2018 Our view of this hyperactive region is obscured by interstellar dust particles, which together absorb virtually every photon streaking toward Earth. Alan Hirshfeld, WSJ, "Book Review: Feeling Gravity’s Pull," 16 Nov. 2018 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 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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First Known Use of photon

1916, in the meaning defined at sense 2

History and Etymology for photon

phot- + -on entry 2

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Statistics for photon

Last Updated

8 Jan 2019

Look-up Popularity

Time Traveler for photon

The first known use of photon was in 1916

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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

photon

noun
pho·​ton | \ ˈfō-ˌtän \

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

More from Merriam-Webster on photon

Rhyming Dictionary: Words that rhyme with photon

Britannica.com: Encyclopedia article about photon

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