Most of the people in the service (4)
I believe the answer is:
mass
I believe this is a triple definition!
'most' is the first definition.
(thesaurus)
'of' acts as a link.
'the people' is the second definition.
('mass' can be a synonym of 'people')
'in' is a link.
'the service' is the third definition.
(church service)
(Other definitions for mass that I've seen before include "Total" , "Large amount, body" , "congregate for > service" , "Religious celebration" , "Service; horde" .)