Music coming across the Middle Eastern river (8)
I believe the answer is:
overture
'music' is the definition.
(I know that overture is a type of music)
'coming across the middle eastern river' is the wordplay.
'coming across' means one lot of letters goes inside another.
'the' becomes 't' (the is pronounced as a 't' sound in some dialects).
'middle eastern' becomes 'over' (I can't justify this - if you can you should give a lot more credence to this answer).
'river' becomes 'ure' (River Ure).
'over'+'ure'='overure'
't' put inside 'overure' is 'OVERTURE'.
Can you help me to learn more?
(Other definitions for overture that I've seen before include "Introductory piece" , "Proposal" , "Opening gambit" , "Orchestral work" , "Approach made with view to starting relationship" .)