planetarium

noun

plan·​e·​tar·​i·​um ˌpla-nə-ˈter-ē-əm 

plural planetariums or planetaria ˌpla-nə-ˈter-ē-ə 

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

For the most accurate location-specific information, consult online planetariums like Stellarium. —Jamie Carter, Forbes.com, 4 Apr. 2025

The opera features live singers and music, an electroacoustic score with surround-sound enhancement, and is accompanied by the planetarium’s wow-worthy HD images of space. —Randy McMullen, The Mercury News, 20 Mar. 2025

Billed as a take on luxury eco-tourism, when complete, the Kosmos Stargazing Resort & Spa will feature 20 futuristic domed stargazing villas with 360-degree views, spread out around a central structure with restaurant (Mediterranean), spa and planetarium. —Larry Olmsted, Forbes, 25 Nov. 2024

Visit The Planetarium The Challenger Learning Center of Tallahassee offers planetarium shows and IMAX movies to entertain and educate kids and adults. —Lisa Cericola, Southern Living, 14 Mar. 2025

Word History

First Known Use

1860, in the meaning defined at sense 1

Rhymes for planetarium

• honorarium
• sanitarium
• aquarium
• herbarium
• ovarium
• puparium
• samarium
• zoarium
• armamentarium
• cerium

Kids Definition

planetarium

noun

plan·​e·​tar·​i·​um ˌplan-ə-ˈter-ē-əm 

plural planetariums or planetaria -ē-ə 

1

: a device that projects images of heavenly bodies on a ceiling shaped like a dome

2

: a building or room housing a planetarium