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) \

Definition of planetarium

1 : a model or representation of the solar system
2a : 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 Forty-five minute planetarium shows by naturalist Chris Mentrek are planned for April 25, May 23 and June 27 in the Robert McCullough Science Center. Joan Rusek, cleveland, 31 Mar. 2021 For the Presidents’ Day holiday, Monday Feb. 21, and Tuesday, Feb. 22, visitors can meet with paleontologist ‘Dino Dan’ O’Dea to learn about dinosaurs and fossils, attend a planetarium show, and ask questions of resident astronomer, Ian Robinson., 10 Feb. 2022 Families are encouraged to volunteer at Retzer, where there will family-friendly activities including a community art project, native wildflower seeds to plant at home and planetarium shows. Chelsey Lewis, Milwaukee Journal Sentinel, 24 Mar. 2022 Located in Houston's Museum District, visitors can walk through a living butterfly habitat, check out the planetarium for spectacular astronomical programs and visit a paleontology hall with giant prehistoric dinosaurs. Rebecca Treon, Chron, 15 Mar. 2022 The new tours are by reservation only and include talks by space enthusiasts plus time inside an inflatable planetarium. Dewayne Bevil,, 5 Nov. 2021 The first part of the experience begins in the Galaxarium, a planetarium-like exhibition where guests will learn about the planet Xander, its history, culture and the heritage of its people. Michelle Spitzer, USA TODAY, 5 Oct. 2021 The planetarium schedule for Feb. 21 and Feb. 22 will be The Sky Tonight, shown at 10:30 a.m., 1 p.m., and 3 p.m., all included with the price of admission., 10 Feb. 2022 The pair ended the night stargazing in a planetarium. Dana Rose Falcone,, 9 Nov. 2021 See More

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'planetarium.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

First Known Use of planetarium

1860, in the meaning defined at sense 1

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The first known use of planetarium was in 1860

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Last Updated

16 May 2022

Cite this Entry

“Planetarium.” Dictionary, Merriam-Webster, Accessed 19 May. 2022.

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More Definitions for planetarium


plan·​e·​tar·​i·​um | \ ˌpla-nə-ˈter-ē-əm How to pronounce planetarium (audio) \

Kids Definition of planetarium

: a building in which there is a device for projecting the images of heavenly bodies on a ceiling shaped like a dome

More from Merriam-Webster on planetarium

Nglish: Translation of planetarium for Spanish Speakers Encyclopedia article about planetarium


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