Psalm about lights (5)
I believe the answer is:
lamps
'lights' is the definition.
(lamp is a kind of light)
'psalm about' is the wordplay.
'about' is an anagram indicator.
'psalm' anagrammed gives 'LAMPS'.
(Other definitions for lamps that I've seen before include "Lights" , "light fittings" , "Devices for giving light" .)