1. [ noun ] (physics,astronomy,optics) an optical device for projecting images of celestial bodies and other astronomical phenomena onto the inner surface of a hemispherical dome
Related terms: optical_device
2. [ noun ] (astronomy) a building housing an instrument for projecting the positions of the planets onto a domed ceiling
Related terms: building
3. [ noun ] an apparatus or model for representing the solar systems
Related terms: model model orrery
Similar spelling:   planetary