[1] : The Collaborative International Dictionary of English v.0.48

nighttime \night"time`\, n.
   the time from dusk to dawn; -- opposed to daytime.
   1913 webster
see also:
daytime 

[2] : WordNet (r) 2.0

nighttime
     adj : happening during or appropriate to the night; "nighttime
           attire"; "the cat's nighttime prowls" ant: daytime
     n : the time after sunset and before sunrise while it is dark
         outside syn: night, dark ant: day
see also:
daytime night dark day 

Nighttime >> N Words
Nighttime, definition of term: Nighttime
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