n.
1.a building housing an instrument for projecting the positions of the planets onto a domed ceiling
2.an optical device for projecting images of celestial bodies and other astronomical phenomena onto the inner surface of a hemispherical dome
3.an apparatus or model for representing the solar systems
Idiom of the Day
raise an objection to (someone or something)
to object to someone or something
My friend raised an objection to my plan to include my parents in our travel plans.