Opportunity given to a number in the church (7)
I believe the answer is:
chancel
'church' is the definition.
(I've seen this before)
'opportunity given to a number' is the wordplay.
'opportunity' becomes 'chance' (synonyms).
'given to' is a charade indicator (letters next to each other).
'a number' becomes 'l' (fifty in Roman numerals).
'chance'+'l'='CHANCEL'
'in the' is the link.
(Other definitions for chancel that I've seen before include "choir and clergy's area" , "Place of altar" , "church, partly" , "Clergy's area of the church" , "where sanctuary may be found" .)