light speed

Definitions of light speed
  1. noun
    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
    synonyms: c, speed of light
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    type of:
    a number representing a quantity assumed to have a fixed value in a specified mathematical context
    speed, velocity
    distance travelled per unit time
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