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
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With Venus blazing in the twilight and a thin crescent moon beside it, Monday evening offers one of the easiest and most photogenic astronomy sights of spring that anyone can enjoy.
—
Jamie Carter, Forbes.com, 16 May 2026
The two main reasons are that different people see constellations in different ways and that, as far as astronomy today is concerned, constellations are not considered star pictures but as specific sky areas.
—Joe Rao, Space.com, 15 May 2026
And Rubin will discover much more than TNOs, too, by virtue of its emphasis on time-domain astronomy—the study of objects such as asteroids, novae, supernovae and active galaxies that move and vary in brightness.
—Phil Plait, Scientific American, 15 May 2026
With it, a new era of astronomy is set to begin.
—Quanta Magazine, 15 May 2026
See All Example Sentences for astronomy
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Jamie Carter, Forbes.com, 16 May 2026
The two main reasons are that different people see constellations in different ways and that, as far as astronomy today is concerned, constellations are not considered star pictures but as specific sky areas.
—Joe Rao, Space.com, 15 May 2026
And Rubin will discover much more than TNOs, too, by virtue of its emphasis on time-domain astronomy—the study of objects such as asteroids, novae, supernovae and active galaxies that move and vary in brightness.
—Phil Plait, Scientific American, 15 May 2026
With it, a new era of astronomy is set to begin.
—Quanta Magazine, 15 May 2026
See All Example Sentences for astronomy
Cite this Entry
“Astronomy.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/astronomy. Accessed 21 May. 2026.
Copy CitationKids 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
noun
-mər
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