Costlier relics to confine to the monastery (8)
I believe the answer is:
cloister
'the monastery' is the definition.
(I've seen this before)
'costlier relics to confine' is the wordplay.
'costlier' anagrams to 'CLOISTER'.
However, I'm unsure how the anagram is indicated.
'to' is the link.
Can you help me to learn more?
(Other definitions for cloister that I've seen before include "Place of religious seclusion, a convent say" , "Covered walk by cathedral etc" , "Covered walk in monastery or convent" , "Cathedral's covered walk" , "Covered monastic walkway" .)