A group of notes sounding in harmony (6)
I believe the answer is:
accord
'in harmony' is the definition.
(I've seen this before)
'a group of notes sounding' is the wordplay.
I cannot quite understand how this works, but
'a' is found in the answer.
'of' could be 'o' and 'o' is located in the answer.
'notes' could be 'cc' (two C's - as in the musical note C) and 'cc' is found in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for accord that I've seen before include "Peace and agreement" , "Myra -, pianist; Rudolf -, Nazi" , "Harmony; treaty" , "Match" , "Model" .)