noun \ˌpla-nə-ˈter-ē-əm\

: a building or room in which images of stars, planets, etc., are shown on a high, curved ceiling

plural plan·e·tar·i·ums or plan·e·tar·ia\-ē-ə\

Full Definition of PLANETARIUM

:  a model or representation of the solar system
a :  an optical device for projecting various celestial images and effects
b :  a building or room housing such a projector

First Known Use of PLANETARIUM



noun    (Concise Encyclopedia)

Institution devoted to popular education in astronomy and related fields, especially space science, whose main teaching tool is a hemispheric screen onto which images of celestial objects as seen from Earth are projected from an instrument also known as a planetarium, or planetarium projector. Major planetariums have extensive exhibit space, museum collections, sizable staffs, projection domes 80 ft (25 m) or more across, and seating capacities of over 600.


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