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.
Appropriately, leading up to the album’s release, Bridgers organized special listening sessions in planetariums. — Mitch Therieau, New Yorker, 14 Aug. 2026 In the meantime, Bridgers’ fans can experience Lost Weekend in planetariums across North America. — Angie Martoccio, Rolling Stone, 14 Aug. 2026 For months, supermarkets, department stores, museums and planetariums across Spain have sold or distributed the glasses, with many pharmacies running out of stock ahead of Wednesday. — Suman Naishadham, Chicago Tribune, 12 Aug. 2026 For months, supermarkets, department stores, museums and planetariums across Spain had sold or distributed the glasses, with many pharmacies running out of stock ahead of Wednesday. — ABC News, 12 Aug. 2026 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

Rhymes for planetarium

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Browse Nearby Words

planetarily
planetarium
planetary
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Cite this Entry

“Planetarium.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/planetarium. Accessed 18 Aug. 2026.

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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

Nglish: Translation of planetarium for Spanish Speakers

Britannica.com: Encyclopedia article about planetarium

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