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

Example Sentences

See Examples For:

lights out

"It means we can potentially design drugs that target the parasite's ARK1 specifically, turning the lights out on malaria without harming the patient."

From Science Daily ● Mar. 5, 2026

Since then those stocks have been lights out, up 76% in 2023, 47.5% in 2024, and 19.3% last year, beating the market every year, according to FactSet.

From Barron's ● Mar. 5, 2026

The strategy shot the lights out when the housing and dotcom bubbles burst.

From The Wall Street Journal ● Feb. 19, 2026

It could be a long, slow descent with the lights out on an RAF jet, or a rapid, corkscrew down in a C-130 transport plane.

From BBC ● Jan. 23, 2026

It was not calming, though, that there were no city lights out there.

From "Kindred" by Octavia Butler

Related Words

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