The initial aria is composed for crowning glory (5)
I believe the answer is:
tiara
'crowning glory' is the definition.
(I've seen this in another clue)
'the initial aria is composed' is the wordplay.
'initial' suggests taking the first letters.
'is composed' indicates anagramming the letters.
The first letter of 'the' is 't'.
'aria' is an anagram of 'iara'.
't'+'iara'='TIARA'
'for' is the link.
(Other definitions for tiara that I've seen before include "expensive headwear" , "Half-crown?" , "Jewelled hair-band" , "Ornamental headpiece" , "Jewelled crescent-shaped headdress" .)