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 new study published in Astronomy and Astrophysics suggests NASA's upcoming Nancy Grace Roman Space Telescope may finally be able to uncover some of them.

From Science Daily • May 15, 2026

"Describing the Heavens: Astronomy from Islamic scientists to Bradford's Abraham Sharp" has been given £3,500 to create a series of family events, workshops and an exhibition.

From BBC • Apr. 1, 2026

The findings, led by researchers at the University of Liège, were published in Astronomy & Astrophysics.

From Science Daily • Mar. 25, 2026

Scientific operations are conducted by the Space Telescope Science Institute in Baltimore, which is run by the Association of Universities for Research in Astronomy.

From Science Daily • Mar. 21, 2026

He was sorely tempted, too, by the perfect, moving model of the galaxy in a large glass ball, which would have meant he never had to take another Astronomy lesson.

From "Harry Potter And The Prisoner Of Azkaban" by J.K. Rowling

Related Words

• astrophysics