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

Maye was lights out for much of the season—there’s a reason he was in the MVP mix—and this will be the first mild weather game the Patriots have played in ages.

From The Wall Street Journal ● Feb. 5, 2026

So Musselman grabbed the gym’s keys, turned the lights out and locked the doors.

From Los Angeles Times ● Dec. 9, 2025

Ms. Paige peeked her head into the room and turned the lights out.

From "The Marvellers" by Dhonielle Clayton

Related Words

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