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

Flammarion imagined that practicing and popularizing astronomy, along with the other sciences, had helped advance Martian society. —Matthew Shindell, Space.com, 29 June 2025

Whelan, the main narrator, portrays Joan, a professor of astronomy with a quiet life. —Audiofile Magazine june 27, Literary Hub, 27 June 2025

These cruises are designed to provide an enhanced learning experience at sea, with in-depth programming focused on topics such as history, architecture, and astronomy. —Jeri Clausing, AFAR Media, 24 June 2025

This will arguably mark the biggest moment in astronomy since the first images from the James Webb Space Telescope (JWST) were revealed in the summer of 2022. —Robert Lea, Space.com, 20 June 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

Rhymes for astronomy

• aeronomy
• agronomy
• autonomy
• economy
• gastronomy
• metonymy
• taxonomy
• deuteronomy

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