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
Suzanne PattersonExamples of light-year in a Sentence
my sister and I are close in age, but personality-wise, there are light-years between us
Recent Examples on the Web
The weak force is so weak, however, that a neutrino could travel through light-years of lead without altering a single atom.
—Quanta Magazine, 8 Apr. 2026
The pink cloud at the center of the shot is the Homunculus Nebula, a vast glowing structure of interstellar dust and gas 7,500 light-years from Earth, according to NASA, created in the wake of a cataclysmic eruption of the double star system Eta Carinae.
—Anthony Wood, Space.com, 8 Apr. 2026
The two nearly identical side-by-side clusters are approximately 7,000 light-years apart.
—Mike Lynch, Twin Cities, 5 Apr. 2026
That’s a long hike—a journey of tens of millions of light-years, sometimes more, ending when one of these wayward rays is absorbed harmlessly by our atmosphere, high above our heads.
—Phil Plait, Scientific American, 3 Apr. 2026
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Quanta Magazine, 8 Apr. 2026
The pink cloud at the center of the shot is the Homunculus Nebula, a vast glowing structure of interstellar dust and gas 7,500 light-years from Earth, according to NASA, created in the wake of a cataclysmic eruption of the double star system Eta Carinae.
—Anthony Wood, Space.com, 8 Apr. 2026
The two nearly identical side-by-side clusters are approximately 7,000 light-years apart.
—Mike Lynch, Twin Cities, 5 Apr. 2026
That’s a long hike—a journey of tens of millions of light-years, sometimes more, ending when one of these wayward rays is absorbed harmlessly by our atmosphere, high above our heads.
—Phil Plait, Scientific American, 3 Apr. 2026
See All Example Sentences for light-year
Cite this Entry
“Light-year.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/light-year. Accessed 11 Apr. 2026.
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