Artist on ball capturing single light (8)
I believe the answer is:
radiance
'light' is the definition.
(radiance is a kind of light)
'artist on ball capturing single' is the wordplay.
'artist' becomes 'ra' (Royal Academician, member of Royal Academy of Arts).
'on' is a charade indicator (letters next to each other).
'ball' becomes 'dance' (I've seen this before**).
'capturing' indicates putting letters inside.
'single' becomes 'i' (one).
'dance' enclosing 'i' is 'diance'.
'ra'+'diance'='RADIANCE'
(Other definitions for radiance that I've seen before include "Brilliance of glow" , "Effulgence" , "Brightness" , "Glow (as of happiness)" , "Beauty" .)