Attention given to a musical composition on the phone (8)
I believe the answer is:
earpiece
'the phone' is the definition.
(synonyms)
'attention given to a musical composition' is the wordplay.
'attention' becomes 'ear' (having someone's ear is having their attention).
'given to' says to put letters next to each other.
'a musical composition' becomes 'piece' ('piece' can be a synonym of 'musical composition').
'ear'+'piece'='EARPIECE'
'on' is the link.
(Other definitions for earpiece that I've seen before include "receiver" , "Part of a telephone" , "Through which one may listen" , "Headset part" , "box?" .)