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.
With its curved ceiling, the 120-seat auditorium serves not just as a film and laser show venue but also as a planetarium. — Veronica Fernandez-Alvarado, Sacbee.com, 16 May 2026 The party will include a trivia challenge and short program in the planetarium and an explanation about the artifacts in the exhibit hall. — Melinda Moore, Chicago Tribune, 11 May 2026 There’s also an adventure center with interactive exhibits, a garden filled with plants native to Hawaii, and a planetarium. — Sharael Kolberg, Travel + Leisure, 26 June 2026 Its arrival signals the return of the Loch Haven Park museum’s big-screen presentations plus planetarium shows and laser-light shows. — Dewayne Bevil, The Orlando Sentinel, 26 May 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

See All Rhymes for planetarium

Browse Nearby Words

planetarily
planetarium
planetary
See all Nearby Words

Cite this Entry

“Planetarium.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/planetarium. Accessed 7 Jul. 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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