Is taking part in the procession - absolute heaven! (8)
I believe the answer is:
paradise
'absolute heaven' is the definition.
'paradise' can be an answer for 'heaven' (paradise is a kind of heaven). I am not sure about the 'absolute' bit.
'is taking part in the procession' is the wordplay.
'taking part in' means one lot of letters goes inside another.
'the procession' becomes 'parade' (parade is a kind of procession).
'is' going inside 'parade' is 'PARADISE'.
Can you help me to learn more?
(Other definitions for paradise that I've seen before include "limbo" , "Poem by 1" , "Place of utter bliss" , "Elysian fields" , "Felicity" .)