English National Opera dates raised in interval (8)
I believe the answer is:
semitone
'interval' is the definition.
(I know that semitone is a type of interval)
'english national opera dates raised' is the wordplay.
'english national opera' becomes 'ENO' (abbreviation).
'dates' becomes 'times' (I can't justify this - if you can you should believe this answer much more).
'raised' says the letters should be written in reverse (going up in a down clue).
'eno'+'times'='enotimes'
'enotimes' reversed gives 'SEMITONE'.
'in' acts as a link.
Can you help me to learn more?
(Other definitions for semitone that I've seen before include "Short musical interval" , "100 cents" , "Small musical interval" , "Interval between adjacent keys, on a piano say" , "One twelfth of an octave" .)