speed of light
Americannoun
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Physics, Optics. a fundamental universal constant, the speed at which light and all forms of electromagnetic radiation travel in a vacuum, standardized as 186,282.4 miles per second (299,792,458 meters per second).
The speed of light, often represented by the letter c, figures prominently in modern physics, as in Einstein’s famous equation E = mc2, which expresses the relation between mass (m) and energy (E).
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an extremely fast rate.
They gobbled those appetizers up at the speed of light.
Etymology
Origin of speed of light
First recorded in 1820–25
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
The ripples move through space at the speed of light, similar to the circular waves that spread across water after a stone is dropped into a pond.
From Science Daily
Grant’s work is delicate: He cleaves each strand of a fiber-optic cable for a clean edge, then uses a machine to fuse the hair-thin filaments, which carry digital data at the speed of light.
As the flare intensified, X ray output surged dramatically, accelerating particles to speeds of 40 to 50 percent of the speed of light, or roughly 431 to 540 million km/h.
From Science Daily
It led Albert Einstein to propose that the speed of light is constant, a cornerstone idea behind his theory of special relativity.
From Science Daily
"If software and AI models move at the speed of light, energy and hardware move at the speed of physics."
From Barron's
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
