noun
photon
FOH-ton
noun
1
The smallest possible unit of light or other electromagnetic energy, with no mass or electric charge.
"A single photon can trigger a chemical reaction in the eye's retina."
How to Use Photon
Learner’s notesIn plain EnglishThe basic particle of light, studied in physics.
Word Forms
photons plural
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A single _____ can trigger a chemical reaction in the eye's retina.
Etymology
Coined from "photo-" plus the particle suffix "-on"; the term was introduced by physicist Leonard Troland in 1916 and later popularized by chemist Gilbert N. Lewis.