Here are the possible solutions for certain light source clue
Answer
Clue
Relevancy
lamp
Clue
Certain light source
Definition
to supply with a light
glorybeam
Clue
"The light" of "I saw the light!"?
laser
Clue
Light in a light show
Light-show light
Light show light
Light in a light show, perhaps
Definition
a source of high-intensity optical, infrared, or ultraviolet radiation produced as a result of stimulated emission maintained within a solid, liquid, or gaseous medium