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

Purchase a ticket in advance, and ride the gondola up to 8,000 feet to see the planetarium and peer through the one-meter telescope. —Kristen Pope, AFAR Media, 22 May 2025

The planetarium at Miami’s Phillip & Patricia Frost Museum of Science will show special Pride laser shows with music from gay icons/allies Elton John, Lady Gaga, David Bowie and Queen. —Rod Stafford Hagwood, Sun Sentinel, 19 May 2025

The planetarium opened in September 1963, according to the city of Elgin’s website. —Mike Danahey, Chicago Tribune, 15 May 2025

For the most accurate location-specific information, consult online planetariums. —Jamie Carter, Forbes.com, 21 Apr. 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