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[plan-i-tair-ee-uh m] /ˌplæn ɪˈtɛər i əm/
noun, plural planetariums, planetaria
[plan-i-tair-ee-uh] /ˌplæn ɪˈtɛər i ə/ (Show IPA)
an apparatus or model representing the planetary system.
a device that produces a representation of the heavens by the use of a number of moving projectors.
the building or room in which such a device is housed.
Origin of planetarium
1765-75; < New Latin, noun use of neuter of Latin planētārius planetary; cf. -arium Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2015.
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Examples from the web for planetarium
  • Reach for the stars with this double-threat tabletop planetarium.
  • They headed back through the mammals and waited for an elevator, which would deliver them to the planetarium.
  • Enjoy our exciting science collections and space travel in our popular planetarium.
  • At the bottom, there was a planetarium, so they would look up at the top and they would see stars.
  • You'd be better off printing your own certificate and donating the money to a local planetarium.
  • Many had students who would fire off things from hoax-promoting websites and they came to the planetarium for explanations.
  • The museum is open six days a week, with planetarium shows on the hour.
  • planetarium shows, raptor programs, kinetic weather machines and life-science exhibits are among the permanent displays.
  • Traditional planetarium shows take us on a virtual tour of stars, planets and galaxies: the outer universe.
  • Discover the wonders of the universe in our planetarium.
British Dictionary definitions for planetarium


noun (pl) -iums, -ia (-ɪə)
an instrument for simulating the apparent motions of the sun, moon, and planets against a background of stars by projecting images of these bodies onto the inside of a domed ceiling
a building in which such an instrument is housed
a model of the solar system, sometimes mechanized to show the relative motions of the planets
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
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Word Origin and History for planetarium

1734, "orrery," Modern Latin, from Late Latin planeta (see planet) + Latin -arium "a place for." Sense of "device for projecting the night sky onto the interior of a dome" is attested from 1929.

Online Etymology Dictionary, © 2010 Douglas Harper
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