A part of the circle gets an itchy rash in the historical stuff (8)
I believe the answer is:
archives
'the historical stuff' is the definition.
The answer and definition can be both man-made objects as well as being singular nouns.
Maybe there's an association between them I don't understand?
'a part of the circle gets an itchy rash' is the wordplay.
'a part of the circle' becomes 'arc' ('arc' is part of 'circle').
'gets' says to put letters next to each other.
'an itchy rash' becomes 'hives' (hives is a kind of rash. I am not sure about the 'itchy' bit.).
'arc'+'hives'='ARCHIVES'
'in' is the link.
Can you help me to learn more?
(Other definitions for archives that I've seen before include "Chronicles" , "Historical records of an institution" , "Public records" , "Collections of old documents" , "Record collection" .)