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light-year
[ lahyt-yeer, -yeer ]
noun
- Astronomy. the distance traversed by light in one mean solar year, about 5.88 trillion mi. (9.46 trillion km): used as a unit in measuring stellar distances. : lt-yr
- light-years,
- a very great distance, especially in development or progress:
The new computer is light-years ahead of the old one.
- a very long time:
It's been light-years since I've seen my childhood friends.
light year
noun
- a unit of distance used in astronomy, equal to the distance travelled by light in one year, i.e. 9.4607 × 10 12kilometres or 0.3066 parsecs
light-year
- The distance that light travels in a vacuum in one year, equal to about 9.46 trillion km (5.88 trillion mi). Light-years are used in measuring interstellar and intergalactic distances.
- Compare astronomical unit
light year
- The distance traveled by light in a year (over five trillion miles); a unit for measuring distances outside the solar system . The star nearest to our sun , Alpha Centauri, is more than four light years away.
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Word History and Origins
Origin of light-year1
First recorded in 1885–90
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