Part of church making intricate patterns (8)
I believe the answer is:
transept
'part of church' is the definition.
('transept' is part of 'church')
'intricate patterns' is the wordplay.
'intricate' indicates an anagram.
'patterns' with letters rearranged gives 'TRANSEPT'.
'making' is the link.
(Other definitions for transept that I've seen before include "Crossing part of a church" , "Arm of church body" , "Part of church intersecting nave" , "Section of church" , "Part of a church - patterns (anag)" .)