photon

[ foh-ton ]

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. : γ

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

photon

/ fō′tŏn′ /

1. 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.
2. See Note at electromagnetic radiationSee Table at subatomic particle

photon

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

Word History and Origins

Origin of photon¹

First recorded in 1900–05; phot- + -on ¹

Example Sentences

A new theory, that explains how light and matter interact at the quantum level has enabled researchers to define for the first time the precise shape of a single photon.

From Science Daily

Reflected, back-scattered photons return from the target object carrying speckle noise, a random type of flaw that occurs in imagery.

From Science Daily

As with other live brain imaging systems that rely on "two-photon microscopy," this scanning light "excites" photon emission from brain cells that have been engineered to fluoresce when stimulated.

From Science Daily

Proton therapy has both biological and physical advantages over traditional radiation therapy using photons.

From Science Daily

They targeted a photochemical reaction in which molecules absorb energy from photons and transfer it to a neighbor.

From Science Magazine