Brilliance, magnificence (9)
I believe the answer is:
splendour
I believe this clue is a double definition.
'brilliance' is the first definition.
(I know that brilliance can be written as splendour)
'magnificence' is the second definition.
(I know that magnificence can be written as splendour)
(Other definitions for splendour that I've seen before include "Magnificent appearance" , "Magnificence, brilliance" , "Brilliant appearance" , "show" , "Grandeur" .)