Part of meal: English course's not first class (6)
I believe the answer is:
entree
'part of meal' is the definition.
(I've seen this before)
'english course's not first class' is the wordplay.
'english' becomes 'e' (abbreviation).
'course' becomes 'n'.
'not first class' becomes 'tree' (I can't justify this - if you can you should give a lot more credence to this answer).
'e'+'n'+'tree'='ENTREE'
Can you help me to learn more?
(Other definitions for entree that I've seen before include "part of meal" , "Means of access - course" , "formal entrance" , "Dish conferring right of access" , "Principal dish of a meal" .)