Brown, perhaps, but there's also one in Scarlet (5)
I believe the answer is:
study
'also one in scarlet' is the definition.
Although both the answer and definition are singular nouns, I can't see how they can define each other.
'brown perhaps but' is the wordplay.
I cannot really understand how this works, but
'perhaps' could be 'y' (I've seen this in other clues) and 'y' is found in the answer.
The remaining letters 'stud' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
'there's' is the link.
Can you help me to learn more?
(Other definitions for study that I've seen before include "Revise" , "Analysis" , "Room for work/reading" , "(Room for) academic work" , "Scrutinize" .)