Planet or eyeball (3)
I believe the answer is:
orb
This clue is a double definition.
'planet' is the first definition.
(I've seen this in another clue)
'eyeball' is the second definition.
(I know that eyeball can be written as orb)
(Other definitions for orb that I've seen before include "Heavenly body" , "The World" , "Sovereign artefact" , "Spherical object or shape" , "Sphere - eye" .)