Lesson remains different (7)
I believe the answer is:
seminar
'lesson' is the definition.
The definition and answer can be both acts as well as being singular nouns.
Perhaps there's a link between them I don't understand?
'remains different' is the wordplay.
'different' is an anagram indicator (letters placed in a different order).
'remains' anagrammed gives 'SEMINAR'.
Can you help me to learn more?
(Other definitions for seminar that I've seen before include "Study group on specific subject" , "Symposium" , "Group discussing" , "Academic class" , "workshop" .)