light-year

noun
\ ˈlīt-ˌyir How to pronounce light-year (audio) \

Definition of light-year

1 : a unit of length in astronomy equal to the distance that light travels in one year in a vacuum or about 5.88 trillion miles (9.46 trillion kilometers)
2 : an extremely large measure of comparison (as of distance, time, or quality) seems like light-years ago has light-years more talent two minutes and yet light-years away from the crowded village— Suzanne Patterson

Synonyms for light-year

Synonyms

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First Known Use of light-year

1867, in the meaning defined at sense 1

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Time Traveler for light-year

Time Traveler

The first known use of light-year was in 1867

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Cite this Entry

“Light-year.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/light-year. Accessed 21 Feb. 2020.

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More Definitions for light-year

light-year

noun
How to pronounce light-year (audio)

English Language Learners Definition of light-year

technical : a unit of distance equal to the distance that light travels in one year (about 5.88 trillion miles or 9.46 trillion kilometers)
used to say that someone or something is much better or more advanced than others
used to refer to a time that is or seems very far away

light-year

noun
\ ˈlīt-ˌyir \

Kids Definition of light-year

: a unit of length in astronomy equal to the distance that light travels in one year or about 5.88 trillion miles (9.46 trillion kilometers)

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