as·​tron·​o·​my | \ ə-ˈsträ-nə-mē How to pronounce astronomy (audio) \
plural astronomies

Definition of astronomy

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

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 The telescope has been called an Apollo moment for science and could start answering some of astronomy’s biggest questions about how the universe began. Washington Post, 27 Dec. 2021 The spacecraft is expected to demonstrate a new form of astronomy, The New York Times reports. Eric Berger, Ars Technica, 10 Dec. 2021 As topics in astronomy go, FRBs are still young and bustling. Adam Mann, Scientific American, 22 Nov. 2021 Mainzer, who has spent her career studying meteors and comets, served as the technical astronomy advisor for the movie. Lindsey Botts, The Arizona Republic, 1 Jan. 2022 The safari camp also has a dining room, lounge, and bar for guests, as well as an infinity pool, a boutique, and an astronomy deck for stargazing. Stefanie Waldek, Travel + Leisure, 31 Dec. 2021 Our desk covers paleontology, astronomy, geology, health and medicine, human origins, technology, and physics. Pages, 30 Dec. 2021 Hawaii is a great destination for many astronomy experiences – the islands offer some fantastic stargazing, and some of the world’s top observatories are located on the Big Island. Valerie Stimac, Forbes, 29 Dec. 2021 Kate Dibiasky, played by Lawrence, is an astronomy graduate student. Andy Meek, BGR, 27 Dec. 2021

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'astronomy.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of astronomy

12th century, in the meaning defined above

History and Etymology for astronomy

Middle English astronomie, from Anglo-French, from Latin astronomia, from Greek, from astr- + -nomia -nomy

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The first known use of astronomy was in the 12th century

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Last Updated

16 Jan 2022

Cite this Entry

“Astronomy.” Dictionary, Merriam-Webster, Accessed 27 Jan. 2022.

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More Definitions for astronomy



English Language Learners Definition of astronomy

: the scientific study of stars, planets, and other objects in outer space


as·​tron·​o·​my | \ ə-ˈsträ-nə-mē How to pronounce astronomy (audio) \

Kids Definition of astronomy

: a science that deals with objects and matter outside the earth's atmosphere and their properties

More from Merriam-Webster on astronomy

Nglish: Translation of astronomy for Spanish Speakers

Britannica English: Translation of astronomy for Arabic Speakers Encyclopedia article about astronomy


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