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.
Home planetariums are often dome or round-shaped and offer more than just lasers making out to be stars on a wall and they can definitely be used as STEM and learning tools. Alexander Cox, Space.com, 3 Sep. 2025 For the most accurate location-specific information, consult online planetariums like Stellarium. Jamie Carter, Forbes.com, 1 Sep. 2025 In 2024 Lowell Observatory expanded with the Astronomy Discovery Center, which has a multistory LED theater called the Lowell Universe Theater, hands-on activities including the Orbits Curiosity Zone and an open sky planetarium. Michael Salerno, AZCentral.com, 26 Aug. 2025 The planetarium has a daily schedule of shows (tickets are $5 per person), including live tours of the night sky. Lisa Cericola, Southern Living, 9 Aug. 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 9 Sep. 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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