Source of light (3,4)
(Other definitions for oil lamp that I've seen before include "Early means of illumination" , "Light that burns kerosene" .)
'source of light' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for sun that I've seen before include "Major star" , "British publication" , "Source of light and heat" , "Dawn riser" , "Star; paper" .)
'source of light' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for lamp that I've seen before include "Source of light, usually portable" , "punch" , "Lighting device in palm" , "Artificial source of illumination" , "Aladdin's - -" .)