Opera group's paper read back in interval (8)
I believe the answer is:
semitone
'interval' is the definition.
(I know that Semitone is a interval)
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for semitone that I've seen before include "Short musical interval" , "Small musical interval" , "Small interval between notes" , "One twelfth of an octave" , "Interval between adjacent keys, on a piano say" .)