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Meaning of light-year

light-year

Pronunciation: (līt'yēr", -yēr'), [key]
— n.
  1. 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. Abbr.: lt-yr
  2. The new computer is light-years ahead of the old one.
    1. a very great distance, esp. in development or progress:The new computer is light-years ahead of the old one.
    2. a very long time:It's been light-years since I've seen my childhood friends.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.