EXAMPLES | WORD ORIGIN noun a quantum of electromagnetic radiation, usually considered as an elementary particle that is its own antiparticle and that has zero rest mass and charge and a spin of one. : γ Symbol Origin of photon
First recorded in
Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
Examples from the Web for photon Contemporary Examples of photon Historical Examples of photon
photon may be retained for a while and emitted again relatively unchanged—the effect observed in luminous paint.
Or there may be an inelastic collision, when the
photon hits an atom and knocks out an electron—the old photoelectric effect.
"Well, you know what happens when a
photon comes in contact with the atomic structure of matter," Kato said.
There were hundreds of scintillations, each caused by a nuclear particle or
photon striking the screen. British Dictionary definitions for photon noun a quantum of electromagnetic radiation, regarded as a particle with zero rest mass and charge, unit spin, and energy equal to the product of the frequency of the radiation and the Planck constant
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
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Word Origin and History for photon n.
"unit of electromagnetic radiation," 1926 in modern sense, from
photo- "light" + -on "unit."
Online Etymology Dictionary, © 2010 Douglas Harper
Medicine definitions for photon n. The quantum of electromagnetic energy, generally regarded as a discrete particle having zero mass, no electric charge, and an indefinitely long lifetime. Related forms pho•ton ′ic adj.
The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
Science definitions for photon The subatomic particle that carries the electromagnetic force and is the quantum of electromagnetic radiation. The photon has a rest mass of zero, but has measurable momentum, exhibits deflection by a gravitational field, and can exert a force. It has no electric charge, has an indefinitely long lifetime, and is its own antiparticle. See Note at electromagnetic radiation. See Table at subatomic particle.
The American Heritage® Science Dictionary
Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Culture definitions for photon
The New Dictionary of Cultural Literacy, Third Edition
Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.