Meanings
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1
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.
The single-imaging optic of the mammalian eye offers some distinct visual advantages. Such lenses can take in photons from a wide range of angles, increasing light sensitivity. They also have high spatial resolution, resolving incoming images in minute detail.
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2
noun
a quantum of electromagnetic radiation
Thesaurus
Etymology
From photo- + -on. Coined by American physicist Leonard Troland in 1916 as a unit of light hitting the retina, and later popularized in a more modern sense by Gilbert N. Lewis, with the term gaining acceptance in the physics community by the late 1920s.