- planetarium - a building housing an instrument for projecting the positions of the planets onto a domed ceiling
--1 is a kind of building, edifice
--1 has part: planetarium- planetarium - an optical device for projecting images of celestial bodies and other astronomical phenomena onto the inner surface of a hemispherical dome
--2 is a kind of optical device
--2 is a part of planetarium- planetarium - an apparatus or model for representing the solar systems
--3 is a kind of model, simulation
--3 has particulars: orrery - planetarium - an optical device for projecting images of celestial bodies and other astronomical phenomena onto the inner surface of a hemispherical dome