# Definitions and Synonyms of *light speed* | Another word for *light speed* | What is *light speed? *

*Definition 1: the speed at which light travels in a vacuum; the constancy and universality of the speed of light is recognized by defining it to be exactly 299,792,458 meters per second - [noun denoting time]*

*Synonyms for light speed in the sense of this definition*

*(**light speed* is a kind of ...) a number representing a quantity assumed to have a fixed value in a specified mathematical context

*light speed*is a kind of ...) a number representing a quantity assumed to have a fixed value in a specified mathematical context

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*"the velocity of light is a constant"*### (*light speed* is a kind of ...) distance travelled per unit time

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