Definition of "lights-out" in English

noun

1. The time at night at which artificial lights are to be turned off, a curfew or bedtime.

2. The prescribed bedtime for persons living in a boarding school or staying in a hospital.

   • We were all expected to be in bed by lights-out.

3. (idiomatic, euphemistic) Something hopeless, over; unconsciousness. [(usually) with for and noun phrase]

   • It's gonna be lights out for you, pal!

4. (idiomatic, sports) A decisive play.

adjective

1. (manufacturing) Done or performed in the dark because of a fully automated working environment. Often describes night shift or third shift work.

   • lights-out manufacturing
   • lights-out production
   • Their night shift is lights-out production. Their day shift handles tooling, setup, and staging to make sure that everything is ready for the next lights-out run.