safety valve

noun

1. a device that, when actuated by a gas or vapor pressure above a predetermined level, opens and allows the gas or vapor to escape until its pressure is reduced to a pressure equal to or below that of the predetermined level. Compare relief valve.
2. a harmless outlet for emotion, tension, etc.

safety valve

noun

1. a valve in a pressure vessel that allows fluid to escape when a predetermined level of pressure has been reached
2. a harmless outlet for emotion, energy, tension, etc

Word History and Origins

Origin of safety valve¹

First recorded in 1805–15

Example Sentences

Coffee aficionados who monitor the temperature of their coffee drinks like the safety valve of a nuclear reactor will probably be happier with hot milk.

From Popular-Science

According to a company report, when water gushed into a drum holding hot coke — an oil byproduct — the reaction triggered a safety valve that relieved the pressure.

From Washington Post

The field hospital was built, in part, as a safety valve for times like this.

From Washington Post

This safety valve allows citizens to sound the alarm and challenge those whose views are hateful and totalitarian.

From The Daily Beast

[W] thout an exchange-rate safety valve you need an alternate way to rebalance economies.

From The Daily Beast

A feed-pump forced water into the boilers; each had a safety-valve with a lever and weight.

From Project Gutenberg

The engine boy having fixed the safety-valve while he fished for eels, caused an explosion of the boiler.

From Project Gutenberg

But Judge Leslie understood and had much sympathy for his pupil—possibly believed in the virtue of the safety-valve.

From Project Gutenberg

Variance appeared to be necessary to their existence; a safety-valve, for the ill humors they could not throw out upon others.

From Project Gutenberg

These he set in the embers, by the side of the former, first opening a safety-valve in each.

From Project Gutenberg