Feature of carol service, with Noel finally included in prison entertainment? (11)

'feature of carol service' is the definition.
Although both the answer and definition are singular nouns, I cannot understand how they can define each other.

'noel finally included in prison entertainment?' is the wordplay.
'finally' indicates one should take the final letters.
'included in' means one lot of letters goes inside another.
'prison' becomes 'can' (the can is American slang for prison).
'entertainment?' becomes 'delight' (I can't explain this - if you can you should believe this answer much more).
The final letter of 'noel' is 'l'.
'can'+'delight'='candelight'
'l' inserted within 'candelight' is 'CANDLELIGHT'.

'with' is the link.

Can you help me to learn more?