Alternatively, chewed main course (5)
I believe the answer is:
orbit
'main course' is the definition.
'orbit' can be an answer for 'course' (I've seen this before). I am not certain of the 'main' bit.
'alternatively chewed' is the wordplay.
'alternatively' becomes 'or'.
'chewed' becomes 'bit'.
'or'+'bit'='ORBIT'
Can you help me to learn more?
(Other definitions for orbit that I've seen before include "Path of one celestial body around another" , "Planet's track" , "Circular path of a planet" , "Sphere of action" , "Circumgyration" .)