Main Entry:

plan·e·tar·i·um

Pronunciation:

\ˌpla-nə-ˈter-ē-əm\

Function:

noun

Inflected Form(s):

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

Date:

1734

1: a model or representation of the solar system2 a: an optical device for projecting various celestial images and effects b: a building or room housing such a projector