Together, sang notes simultaneously, taking exercise (8)
I believe the answer is:
chorused
'together sang' is the definition.
'chorused' can be an answer for 'sang' (chorusing is a kind of singing). I'm not sure about the 'together' bit.
'notes simultaneously taking exercise' is the wordplay.
'notes simultaneously' becomes 'chord' (I can't explain this - if you can you should believe this answer much more).
'taking' means one lot of letters goes inside another.
'exercise' becomes 'use' (synonyms).
'chord' going around 'use' is 'CHORUSED'.
Can you help me to learn more?
(Another definition for chorused that I've seen is " Sang".)