Ring, Henry, ring (4)
I believe the answer is:
halo
'ring' is the definition.
(I've seen this before)
'henry ring' is the wordplay.
'henry' becomes 'hal'.
'ring' becomes 'o'.
'hal'+'o'='HALO'
(Other definitions for halo that I've seen before include "Circle painted over saint's head" , "Crown" , "Nimbus" , "Sign of holiness" , "Light around sun, saint" .)