Question

Out Like a Light fast asleep; suddenly unconscious

Accepted Answer

Given a strong anesthetic, the patient was out like a light. In America in the 20th century, when the wonders of electricity spread across the land, people could turn on and shut off lights with just a flick of a switch. By the middle of the century, "out like a light" was a way of saying that a person had fallen asleep very quickly or had been knocked out or drugged into unconsciousness in a matter of seconds.

Idiom	Out Like a Light
Example	Given a strong anesthetic, the patient was out like a light.
Meaning	fast asleep; suddenly unconscious
Origin	In America in the 20th century, when the wonders of electricity spread across the land, people could turn on and shut off lights with just a flick of a switch. By the middle of the century, "out like a light" was a way of saying that a person had fallen asleep very quickly or had been knocked out or drugged into unconsciousness in a matter of seconds.

Light Century Strong Anesthetic Patient Fast Asleep Suddenly