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

"A year in orbit pushes both hardware and humans into a different operational regime compared with the shorter Shenzhou missions of the programme's earlier phases," the professor of physics and astronomy told AFP.

From Barron's • May 23, 2026

The Observatory, one of the UK's oldest purpose-built scientific institutions, is known for its contributions to astronomy.

From BBC • May 18, 2026

To better understand how planets form and evolve, researchers from astronomy, planetary science, and Earth science are increasingly working together.

From Science Daily • Apr. 21, 2026

“This space shuttle is everything rolled into one that my husband loved: astronomy, innovation, exploration, science, math and especially children,” Oschin said.

From Los Angeles Times • Apr. 13, 2026

Not that Halley seemed to care much about the prospects for his career in astronomy at this time.

From "The Scientists" by John Gribbin

Related Words

• astrophysics