lights out

American  

noun

1. Chiefly Military. a signal, usually by drum or bugle, that all or certain camp or barracks lights are to be extinguished for the night.

2. bedtime.

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lights out British  

noun

1. the time when those resident at an institution, such as soldiers in barracks or children at a boarding school, are expected to retire to bed

2. a fanfare or other signal indicating or signifying this

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Etymology

Origin of lights out

First recorded in 1865–70

Related Words

• collapse
• departure
• dissolution
• downfall
• extinction
• failure
• passing
• termination