planetarium

noun

plan·​e·​tar·​i·​um ˌpla-nə-ˈter-ē-əm How to pronounce planetarium (audio)
plural planetariums or planetaria ˌpla-nə-ˈter-ē-ə How to pronounce planetarium (audio)
1
: a model or representation of the solar system
2
a
: an optical device for projecting various celestial images and effects
b
: a building or room housing such a projector

Examples of planetarium 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.
For a list of all the planetariums to visit to view the meteor showers, check out our guide. Tiffany Acosta, AZCentral.com, 8 July 2025 The opto-mechanical planetarium projector remains a technological wonder of the modern world. Martin Bush, Space.com, 5 July 2025 The planetarium offers presentations in English and provides transportation to and from the city center. Carolyn Heller, Forbes.com, 19 June 2025 Moreover, for the most accurate location-specific information, refer back to online planetariums such as Stellarium. Valerie Mesa, People.com, 21 May 2025 See All Example Sentences for planetarium

Word History

First Known Use

1860, in the meaning defined at sense 1

Time Traveler
The first known use of planetarium was in 1860

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Cite this Entry

“Planetarium.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/planetarium. Accessed 15 Jul. 2025.

Kids Definition

planetarium

noun
plan·​e·​tar·​i·​um ˌplan-ə-ˈter-ē-əm How to pronounce planetarium (audio)
plural planetariums or planetaria -ē-ə How to pronounce planetarium (audio)
1
: a device that projects images of heavenly bodies on a ceiling shaped like a dome
2
: a building or room housing a planetarium

More from Merriam-Webster on planetarium

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