ephemeris

noun

ephem·​er·​is i-ˈfe-mə-rəs How to pronounce ephemeris (audio)
plural ephemerides ˌe-fə-ˈmer-ə-ˌdēz How to pronounce ephemeris (audio)
: a tabular statement of the assigned places of a celestial body for regular intervals

Examples of ephemeris in a Sentence

Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
The ephemerides were the ancestors of astronomical tables, which still exist. — James Byrne, The Conversation, 17 Mar. 2025 In earlier times, people used to calculate the information manually by creating an ephemeris based on the stars at the time of birth, which is not necessary anymore. — Lisa Stardust, Peoplemag, 12 Apr. 2024

Word History

Etymology

Latin, diary, ephemeris, from Greek ephēmeris, from ephēmeros

First Known Use

1508, in the meaning defined above

Time Traveler
The first known use of ephemeris was in 1508

Phrases Containing ephemeris

Rhymes for ephemeris

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Browse Nearby Words

Ephemeridae
ephemeris
ephemeris time
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Cite this Entry

“Ephemeris.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/ephemeris. Accessed 24 Apr. 2025.

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More from Merriam-Webster on ephemeris

Britannica.com: Encyclopedia article about ephemeris

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