noun.
The elementary particle of light and other electromagnetic radiation; the quantum of electromagnetic energy. The photon is the massless, neutral vector boson that mediates electromagnetic interactions.
noun.
The quantum of light and other electromagnetic energy, regarded as a discrete particle having zero rest mass, no electric charge, and an indefinitely long lifetime. It is a gauge boson.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
noun.
a quantum of electromagnetic radiation; an elementary particle that is its own antiparticle
Word Usage
"The measurement of the twin photon is intentionally delayed (8 nanoseconds) after the measurement of the signal photon."