astronomy

noun

as·​tron·​o·​my ə-ˈsträ-nə-mē 

plural astronomies

: the study of objects and matter outside the earth's atmosphere and of their physical and chemical properties

Did you know?

The Difference Between Astronomy and Astrology

Some may find it easy to confuse astronomy and astrology. At one time, these two words actually were synonymous (that is, astronomy once meant what astrology means today), but they have since moved apart from each other. In current use, astronomy is concerned with “the study of objects and matter outside the earth's atmosphere,” while astrology is the purported divination of how stars and planets influence our lives. Put bluntly, astronomy is a science, and astrology is not.

Examples of astronomy in a Sentence

Recent Examples on the Web

In the absence of competition, American astronomy enthusiasts have paid hundreds of millions of dollars for overpriced products during the two decades, in which the conspirators controlled the market, the documents allege. —Tereza Pultarova, Space.com, 17 Jan. 2025

Check my main feed for more in-depth articles on stargazing, astronomy, eclipses and more. —Jamie Carter, Forbes, 13 Jan. 2025

The Mount Wilson Observatory is an important site in the history of modern astronomy. —Alexandra E. Petri, New York Times, 10 Jan. 2025

Traveling To Consider attending a community astronomy night, where night-sky experts will show you the stars and planets via telescope. —Stephanie Vermillion, Outside Online, 10 Jan. 2025

Word History

Etymology

Middle English astronomie "study of celestial bodies, including their possible influence on human affairs," borrowed from Anglo-French & Latin; Anglo-French astronomie, borrowed from Latin astronomia, borrowed from Greek astronomía "study of the stars, especially their movements," from astro- astro- + -nomia -nomy

First Known Use

12th century, in the meaning defined above

Phrases Containing astronomy

• radar astronomy
• radio astronomy
• X-ray astronomy

Kids Definition

astronomy

noun

as·​tron·​o·​my ə-ˈsträn-ə-mē 

plural astronomies

: the science of the heavenly bodies and of their sizes, motions, and composition

astronomer

-mər

noun