Engine in church in US state (7)
I believe the answer is:
'engine' is the definition.
(I've seen this before)
'church in us state' is the wordplay.
'church' becomes 'ch' (common abbreviation).
'in' means one lot of letters goes inside another.
'us state' becomes 'maine' (I've seen this before).
'ch' put inside 'maine' is 'MACHINE'.
'in' acts as a link.
(Other definitions for machine that I've seen before include "Device for work" , "Nice ham (anag.)" , "Motor" , "Chain me to power-driven apparatus" , "Powered mechanism" .)