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

Liberal Democrat Morgan has also met with world-leading physicist Prof Brian Cox, who warned that the cuts could be as high £162m, roughly 30% of particle physics, astronomy and nuclear physics research.

From BBC • Jul. 2, 2026

According to Dr. Daniel Williams, the growing catalog represents a fundamental shift in what gravitational wave astronomy can achieve.

From Science Daily • Jul. 2, 2026

The 1.7 million satellites that companies are aiming to launch into Earth's orbit in the coming years will have "devastating consequences for astronomy", new research warned Wednesday.

From Barron's • Jul. 1, 2026

The authors' main argument draws inspiration from the Copernican tradition in astronomy.

From Science Daily • Jun. 24, 2026

His motivation for this work came from his interest in astronomy, where the need for accurate timekeeping had long been obvious, but was becoming more pressing as more accurate observing instruments were designed.

From "The Scientists" by John Gribbin

Related Words

• astrophysics