Patterns used for part of a church (8)
I believe the answer is:
transept
'part of a church' is the definition.
('transept' is part of 'church')
'patterns used' is the wordplay.
'used' indicates anagramming the letters.
'patterns' with letters rearranged gives 'TRANSEPT'.
'for' is the link.
(Other definitions for transept that I've seen before include "Something dividing church in two" , "Part of a church - patterns (anag)" , "always running north to south" , "Side part of a church" , "Section of church" .)