Light entering for each supplication (6)
I believe the answer is:
prayer
'supplication' is the definition.
(I know that supplication can be written as prayer)
'light entering for each' is the wordplay.
'light' becomes 'ray' (ray is a kind of light).
'entering' indicates putting letters inside.
'for each' becomes 'per' (per person).
'ray' inserted into 'per' is 'PRAYER'.
(Other definitions for prayer that I've seen before include "Request to deity" , "Earnest hope" , "Act of supplication to a deity" , "Intended communication with a deity" , "Devotion" .)