astrometry

noun

as·​trom·​e·​try ə-ˈsträ-mə-trē How to pronounce astrometry (audio)
: a branch of astronomy that deals with measurements (as of positions and movements) of celestial bodies
astrometric adjective

Examples of astrometry 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.
But astrometry needs accurate observational data taken for a long time. Toshi Hirabayashi, The Conversation, 25 June 2025 At the heart of Gaia’s mapmaking is a technique called astrometry, the measurement of celestial positions and motions in the plane of the sky. Lee Billings, Scientific American, 18 June 2025 But recently, astronomers were able to combine astrometry and direct imaging together and find an exoplanet. Jackie Appel, Popular Mechanics, 6 May 2023 There’s astrometry, where scientists look for how an exoplanet causes a host star to move in relation to other stars. Jackie Appel, Popular Mechanics, 6 May 2023 But astrometry can reveal planets, too: A planet orbiting a star can cause the star’s position to cyclically shift ever-so-slightly, oscillating back and forth in the plane of the sky. Nola Taylor Tillman, Scientific American, 13 Apr. 2023 Gaia and Hipparcos were both meant to map the Milky Way’s stars (rather than its planets) using a technique called astrometry to precisely track stellar positions, distances and motions. Nola Taylor Tillman, Scientific American, 13 Apr. 2023 To map these stars, astronomers use astrometry — measuring the precise positions of stars. Liz Kruesi, Discover Magazine, 23 Sep. 2016 Everyone was convinced the job was going to be done with astrometry. Andrew Grant, Discover Magazine, 27 Nov. 2012

Word History

Etymology

astro- + -metry

First Known Use

1811, in the meaning defined above

Time Traveler
The first known use of astrometry was in 1811

Browse Nearby Words

Cite this Entry

“Astrometry.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/astrometry. Accessed 1 Jul. 2025.

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