photon
n. countable C1 Advanced US //ˈfoʊˌtɑn// UK //fˈəʊtɒn// pho·ton
n. a tiny particle of light. It is the smallest possible piece of light energy.
n. the quantum of the electromagnetic field, including electromagnetic radiation such as light. It carries energy proportional to the radiation frequency and has zero rest mass.
A photon is a tiny particle of light.
When a photon hits a solar panel, it can knock an electron loose to create an electric current.
In quantum mechanics, light exhibits both wave-like and particle-like properties, with the photon representing the discrete packet of energy that mediates electromagnetic interactions.
Usage
Commonly used in physics and optics; often appears in the plural when discussing light intensity.