New lamp left off, producing hours of darkness (5)

I believe the answer is:

night

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'hours of darkness' is the definition.
(dark time of day)

I cannot understand how the rest of the clue works.

(Other definitions for night that I've seen before include "Opposite of day" , "Thing (anag)" , "Time of darkness" , "Hours of darkness" , "Sunset to sunrise" .)

I've seen this clue in The Telegraph.

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