armillary spherear·mil·lar·y sphere
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.