Afterwards take a student to one side (7)
I believe the answer is:
lateral
'side' is the definition.
('lateral' can be a synonym of 'side')
'afterwards take a student to one' is the wordplay.
'afterwards' becomes 'later' ('later' can be a synonym of 'afterwards').
'take' means one lot of letters go next to another.
'a student' becomes 'l' (as in L-plates for learner drivers).
'to' means one lot of letters go next to another (I've seen this in other clues).
'one' becomes 'a'.
'l' put after 'a' is 'al'.
'later' next to 'al' is 'LATERAL'.
(Other definitions for lateral that I've seen before include "belonging to the side" , "Sideways, like creative thinking" , "Edgeways" , "One type of thinking" , "Tall ear (anag.)" .)