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\ ˈlīts-ˈau̇t 
\
\Definition of lights-out
1 : a command or signal for putting out lights
2 : a prescribed bedtime for persons living under discipline
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More Definitions for lights-out
lights-out
nounEnglish Language Learners Definition of lights-out
: a time when people (such as soldiers, prisoners, or students) are required to turn out the lights and go to bed
See the full definition for lights-out in the English Language Learners Dictionary
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The first known use of lights-out was in 1868
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