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

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.

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.

12th century, in the meaning defined above

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

Cite this Entry

Astronomy. Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/astronomy. Accessed 11 Mar. 2020.

More Definitions for astronomy

: a science concerned with objects and matter outside the earth's atmosphere and of their motions and makeup

Comments on astronomy

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Astronomy | Definition of Astronomy by Merriam-Webster