Definition of light year in English:

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light year



1 Astronomy A unit of astronomical distance equivalent to the distance that light travels in one year, which is 9.4607 × 1012 km (nearly 6 million million miles).
Example sentences
  • Neutrinos are ghostly particles that can travel through a light year of lead and they have no problem escaping directly from the core of a supernova.
  • If a star exploded a light year away, the increased cosmic ray intensity could have killed the animals by giving them all an intense dose of radiation.
  • A light year is a convenient means of distance measurement because conventional means in miles or kilometers is so large as to thwart true appreciation.
1.1 (light years) informal A long distance or great amount: the new range puts them light years ahead of the competition
More example sentences
  • Defensively, they are light years ahead of where they were last season.
  • In some ways, there are breeds of gull and sea bird who are light years ahead of us on the long-term commitment front and don't seem to have the same issues that we do.
  • The standard of director to be found in the country's boardrooms is light years ahead of the small - town businessmen who formerly ruled the roost.
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