Dusk to dawn (5)
I believe the answer is:
night
'dusk to dawn' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for night that I've seen before include "Hours of darkness" , "''Twas the ... before Christmas, when all through the house / Not a creature was stirring, not even a mouse''" , "Dark period" , "See 8" , "Illumination needed now" .)