astronomy

American  

[uh-stron-uh-mee] / əˈstrɒn ə mi /

noun

1. the science that deals with the material universe beyond the earth's atmosphere.

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astronomy British  

/ əˈstrɒnəmɪ /

noun

1. the scientific study of the individual celestial bodies (excluding the earth) and of the universe as a whole. Its various branches include astrometry, astrodynamics, cosmology, and astrophysics

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astronomy Scientific  

/ ə-strŏn′ə-mē /

1. The scientific study of the universe and the objects in it, including stars, planets, nebulae, and galaxies. Astronomy deals with the position, size, motion, composition, energy, and evolution of celestial objects. Astronomers analyze not only visible light but also radio waves, x-rays, and other ranges of radiation that come from sources outside the Earth's atmosphere.

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astronomy Cultural  

1. The science that deals with the universe beyond the Earth. It describes the nature, position, and motion of the stars, planets, and other objects in the skies, and their relation to the Earth.

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Etymology

Origin of astronomy

First recorded in 1175–1225; Middle English astronomie, from Anglo-French, from Latin astronomia, from Greek; equivalent to astro- + -nomy

Compare meaning

How does astronomy compare to similar and commonly confused words? Explore the most common comparisons:

• astronomy vs. astrology

Explanation

Astronomy is the science that looks up: at stars, at other planets, at solar systems, at galaxies, and at everything else in the universe. The Ancient Greeks used the word astron for "star," so it only makes sense that astronomy would involve the study or the stars (and other unearthly topics). Someone who studies or works in astronomy is an astronomer, and one of the main tools of the trade is the telescope. As telescopes get more and more powerful, astronomers learn more and more about what's going on out there, such as how old a star or planet is. If you ever wondered what's out there besides the Earth, you should learn more about astronomy.

Example Sentences

"It'll be exciting, you know, in a slightly scary way, when they go behind the moon," Derek Buzasi, a professor of astronomy and astrophysics at the University of Chicago, told AFP.

From Barron's • Apr. 5, 2026

While religion provides answers, astronomy offers another way to search for them, grounding me like a kind of cosmic anchor.

From The Wall Street Journal • Mar. 31, 2026

UMD astronomy research scientist Tony Farnham and former postdoctoral researcher Juan Rizos developed specialized techniques to remove shadows cast by boulders and lighting artifacts from the photos.

From Science Daily • Mar. 8, 2026

If you don't have access to binoculars or a telescope you might be able to attend a local astronomy society event to get a better look.

From BBC • Feb. 27, 2026

Copernicus tells us that he engaged in a systematic programme of reading as he struggled with the formulation of his new astronomy.

From "The Invention of Science" by David Wootton

Related Words

• astrophysics