photon

[foh-ton] /ˈfoʊ tɒn/
noun
1.
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. Symbol: γ.
Also called light quantum.
Origin
1900-05; phot- + -on1
Examples from the web for photon
  • When a photon strikes its surface, it bounces off, imparting its momentum to the sail.
  • When the atom drops back to a lower energy level, it emits a photon.
  • Quantum coherence describes how more than one molecule interacts with the same energy from one incoming photon at the same time.
  • Once entangled, a photon can carry any information stored in the atom's quantum state to other parts of the computer.
  • And the opposite in the case of a photon traveling away from a source of gravity.
  • If these particles zip through water or ice, they leave faint blue trails of light that can be seen by sensitive photon detectors.
  • Not a rocket with its boosters on full blast nor a photon of light.
  • The material included a layer of equally spaced quantum dots, which emit lots of light when struck with one photon.
  • When they fall back to a lower state a photon is emitted, and the wavelength of the photon determines the color.
  • Each photon of laser light carries a tiny amount of momentum.
British Dictionary definitions for photon

photon

/ˈfəʊtɒn/
noun
1.
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
Word Origin and History for photon
n.

"unit of electromagnetic radiation," 1926 in modern sense, from photo- "light" + -on "unit."

photon in Medicine

photon pho·ton (fō'tŏn')
n.
The quantum of electromagnetic energy, generally regarded as a discrete particle having zero mass, no electric charge, and an indefinitely long lifetime.

pho·ton'ic adj.
photon in Science
photon
  (fō'tŏn')   
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.
photon in Culture
photon [(foh-ton)]

The quantum, or bundle of energy, in which light and other forms of electromagnetic radiation are emitted. (See atom.)