light-year

noun

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 villageSuzanne Patterson

Examples of light-year in a Sentence

Recent Examples on the Web Canopus The star Canopus is found in the constellation Carina, which is located 310 light-years from Earth. Elizabeth Gamillo, Discover Magazine, 5 Mar. 2024 The spiral arms of the Milky Way stretch about 100,000 light-years, and the sun (and our solar system) reside about two-thirds of the way out from the center of the galaxy. Dean Regas, The Enquirer, 2 Mar. 2024 Nearby will be orangey Aldebaran, the brightest star in the constellation of Taurus and about 65 light-years from the solar system. Jamie Carter, Forbes, 29 Feb. 2024 On thousands of sterile exoplanets, throughout all the vast sphere of stars within a hundred light-years of the sun, life was about to blossom—life, or something else. Karl Schroeder, IEEE Spectrum, 24 Feb. 2024 Astronomers observed a dead star, known as a white dwarf, located about 63 light-years away from Earth using the European Southern Observatory’s Very Large Telescope in Chile. Ashley Strickland, CNN, 26 Feb. 2024 No supernova had been seen so close to our planet since Kepler’s Supernova in 1604, when a star detonated within our galaxy at a distance of about 20,000 light-years. Jonathan O'Callaghan, Scientific American, 23 Feb. 2024 Detected 12 billion light-years distant in the early universe, the object is a quasar that's 500 trillion times more luminous than the sun. Jamie Carter, Forbes, 20 Feb. 2024 Stunning image shows star forming 5,900 light-years from Earth Private-sector lunar lander launched on historic moon mission More Caitlin O'Kane Caitlin O'Kane is a New York City journalist who works on the CBS News social media team as a senior manager of content and production. Caitlin O'Kane, CBS News, 19 Feb. 2024

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'light-year.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History

First Known Use

1864, in the meaning defined at sense 1

Time Traveler
The first known use of light-year was in 1864

Dictionary Entries Near light-year

Cite this Entry

“Light-year.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/light-year. Accessed 18 Mar. 2024.

Kids Definition

light-year

noun
ˈlīt-ˌyi(ə)r
1
: a unit of length in astronomy equal to the distance that light travels in one year or 5,880,000,000,000 miles (9,460,000,000,000 kilometers)
2
: a very great distance especially in progress
light-years ahead in design

More from Merriam-Webster on light-year

Last Updated: - Updated example sentences
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!