Merriam-Webster's Collegiate® Dictionary, 11th Edition
ORB
I. noun
Etymology: Middle English, from Middle French orbe, from Latin orbis circle, disk, orb
Date: 15th century
any of the concentric spheres in old astronomy surrounding the earth and carrying the celestial bodies in their revolutions, something circular ; circle , orbit , a spherical body, eye , a sphere surmounted by a cross symbolizing kingly power and justice,
II. verb
Date: 1600
transitive verb to form into a disk or circle, encircle , surround , enclose , intransitive verb to move in an orbit