One might seek comfort in this tranquil church song (4,5)
I believe the answer is:
easy chair
'one might seek comfort in this' is the definition.
The definition suggests a singular noun which matches the answer.
'tranquil church song' is the wordplay.
'tranquil' becomes 'easy' (I've seen this in another clue).
'church' becomes 'ch' (common abbreviation).
'song' becomes 'air' (I've seen this before).
'easy'+'ch'+'air'='EASY CHAIR'
Can you help me to learn more?
(Other definitions for easy chair that I've seen before include "Lounge feature" , "It's comfortable to sit in - sounds like it" , "ambitious professor avoids" , "Comfy seat" , "comfortable position" .)