Round object (5)
(Other definitions for wheel that I've seen before include "No need to re-invent it!" , "revolutionary device" , "Circular object (in no need of re-invention!)" , "Cog" , "Revolutionary invention!" .)
'round object' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for sphere that I've seen before include "Vault of heaven" , "Round object" , "Globe or ball" , "Perfectly round solid geometric figure" , "Perfect round" .)