an ancient astronomical sighting instrument representing the great circles of the horizon, the ecliptic, the meridian, etc.
Origin of armillary spherefrom Classical Latin armilla, armlet, bracelet from armus: see arm
An old astronomical model with solid, usually metal rings, all great circles of a single sphere, used to display relationships among the principal celestial circles.
Origin of armillary sphereTranslation of French sphère armillaire from Latin armilla bracelet from armus shoulder ; see ar- in Indo-European roots.
by Adam Heroldt
(plural armillary spheres)
- An instrument consisting of graduated metal circles used to represent the motions of celestial bodies around the earth.