In general, a style of sleeve (6)
I believe the answer is:
raglan
'style of sleeve' is the definition.
(I've seen this before)
'in general a' is the wordplay.
I cannot really understand how this works, but
'a' could be 'an' and 'an' is found within the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for raglan that I've seen before include "Garment defined by its sleeves" , "Br. Crimean commander; overcoat" , "Style of sleeve" , "Crimean commander; type of coat" , "Type of sleeve or overcoat" .)