Church melody form — Christian, ultimately (4)
I believe the answer is:
hymn
'church melody form christian ultimately' is the definition.
I can't tell whether this defines the answer.
'church melody form christian ultimately' is the wordplay.
'ultimately' indicates one should take the final letters.
The last letters of 'church melody form christian' are 'HYMN'.
(Other definitions for hymn that I've seen before include "Godly song" , "religious works" , "Song of worship" , "One sung in church" , "Song sung in church" .)