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planetarium Syllabification: plan·e·tar·i·um
Pronunciation: /ˌplanəˈterēəm/

Definition of planetarium in English:

noun (plural planetariums or planetaria-ˈte(ə)rēə)

1A building in which images of stars, planets, and constellations are projected on the inner surface of a dome for public entertainment or education.
Example sentences
  • He announced to his wife that he was going to educate the public by building a planetarium in the back room of their house.
  • Although not terribly well known, the Observatorio Astronomico de Mallorca has a working planetarium and offers public skywatching using telescopes sufficiently powerful to study Jupiter, Mars, Saturn, Venus and Mercury.
  • Cosmic Microwave Background: The New Cosmology and other elements of the AstroBulletin are made available to museums, science centers, planetariums, and other public spaces nationwide and around the world.
1.1A device used to project images of stars, planets, and constellations.
Example sentences
  • While astronomers were radically expanding their view of the universe in the early part of the twentieth century, a new invention was also fueling a rising public enthusiasm: the planetarium.
  • A planetarium can do stars and project slides on the ceiling, maybe make a laser dance in one place, and that's about it.
  • The planetarium projects bright stars and constellations visible in the Southern Hemisphere on your walls and ceilings.
2 another term for orrery.
Example sentences
  • He wrote Theorica Planetarum which describes the construction of a planetarium, the first to be described by a European.
  • He also included instructions on building a planetarium as well as its geometrical description.


Mid 18th century: modern Latin, from Latin planetarius 'relating to the planets'.

Words that rhyme with planetarium

aquarium, armamentarium, barium, caldarium, cinerarium, columbarium, dolphinarium, frigidarium, herbarium, honorarium, rosarium, sanitarium, solarium, sudarium, tepidarium, terrarium, vivarium

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