Comfortably in a big book about fashion centre (6)
I believe the answer is:
'comfortably in' is the definition.
'at home' can be an answer for 'in' (someone at home is 'in'). I am unsure of the 'comfortably' bit.
'a big book about fashion centre' is the wordplay.
'big book' becomes 'tome' (term for a large or heavy book).
'about' means one lot of letters goes inside another.
'centre' indicates the central letters.
The middle of 'fashion' is 'h'.
'tome' enclosing 'h' is 'thome'.
'a'+'thome'='ATHOME'
Can you help me to learn more?
(Other definitions for at-home that I've seen before include "Available to visitors, quite comfortable" , "Comfortable - in one's own country" , "Domestic gathering" , "In (for a party?)" , "Not away - available to visitors" .)