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
Polaris is perched 433 light-years, or just over 2500 trillion miles, above the North Pole.
—Mike Lynch, Twin Cities, 19 Apr. 2026
Earthshine is particularly easy to spot around this time and the relatively weak glow from the moon's sunlit crescent won't be enough to obscure the light of the Pleiades, as its stars — more than 1,000 in total —shine about 445 light-years away in the constellation Taurus.
—Anthony Wood, Space.com, 19 Apr. 2026
Using data from two international networks of radio telescopes, researchers pinned down the energetics of jets erupting from a black hole in a system called Cygnus X-1, some 7,200 light-years from Earth.
—Lee Billings, Scientific American, 16 Apr. 2026
At more than 440 million light-years away from Earth, the two black holes are inseparable even when seen through astronomy’s most advanced tools.
—Andrew Paul, Popular Science, 8 Apr. 2026
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Mike Lynch, Twin Cities, 19 Apr. 2026
Earthshine is particularly easy to spot around this time and the relatively weak glow from the moon's sunlit crescent won't be enough to obscure the light of the Pleiades, as its stars — more than 1,000 in total —shine about 445 light-years away in the constellation Taurus.
—Anthony Wood, Space.com, 19 Apr. 2026
Using data from two international networks of radio telescopes, researchers pinned down the energetics of jets erupting from a black hole in a system called Cygnus X-1, some 7,200 light-years from Earth.
—Lee Billings, Scientific American, 16 Apr. 2026
At more than 440 million light-years away from Earth, the two black holes are inseparable even when seen through astronomy’s most advanced tools.
—Andrew Paul, Popular Science, 8 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 22 Apr. 2026.
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