Ring Henry, love (4)
I believe the answer is:
halo
'ring' is the definition.
(I know that ring can be written as halo)
'henry love' is the wordplay.
'henry' becomes 'hal' (short for Henry).
'love' becomes 'o' (love means zero in tennis).
'hal'+'o'='HALO'
(Other definitions for halo that I've seen before include "Symbol of sainthood" , "Hagiological aura featured in Christian art" , "Saintly ring" , "Corona" , "Ring of light (signifying holiness)" .)