A church provides one (3)
I believe the answer is:
ace
'one' is the definition.
('ace' can be a synonym of 'one')
'a church' is the wordplay.
'church' becomes 'ce' (abbreviation for Church of England**).
'a'+'ce'='ACE'
'provides' acts as a link.
(Other definitions for ace that I've seen before include "Great" , "Best type of tennis serve" , "Single unit on playing cards" , "Unreturnable serve" , "Excellent" .)