Meaning of “light year” in the English Dictionary


"light year" in English

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(Definition of “light year” from the Cambridge Advanced Learner’s Dictionary & Thesaurus © Cambridge University Press)

"light year" in American English

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light yearnoun [ C ]

us /ˈlɑɪt ˌyɪər/

earth science the great distance that light travels in one year; about 5,880,000,000,000 miles or 9,460,000,000,000 kilometers

earth science People sometimes say light years to talk about an extremely long distance or time:

When I was a young man, being 50 seemed light years away.

(Definition of “light year” from the Cambridge Academic Content Dictionary © Cambridge University Press)