A round body
ball, globule, orb; see circle 1.
The celestial sphere
heavens, sky, planetary sphere, primum mobile (Latin).
province, compass, sphere of influence, walk of life, field.
Another word for sphere
An area within which something or someone exists, acts, or has influence or power: ambit, compass, extension, extent, orbit, purview, range, reach, realm, scope, sweep, swing. See territory