safety valve

American  

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.

2. a harmless outlet for emotion, tension, etc.

---

safety valve British  

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

---

Etymology

Origin of safety valve

First recorded in 1805–15

Example Sentences

In addition, they note that now, parents will still have access to the debt, but thanks to the changes to repayment, they won’t have much of a safety valve if it becomes unmanageable.

From MarketWatch • Jul. 1, 2026

Britain’s parliamentary system creates a ready vehicle for leadership changes between elections, and society historically has used that process as a political safety valve.

From The Wall Street Journal • Jun. 25, 2026

It is an essential safety valve that remains "effective only if the conflict doesn't last too long", cautioned Perrin.

From Barron's • Mar. 10, 2026

In that incident, the board’s investigation found multiple safety failures, including a severely eroded safety valve that allowed flammable gases to dangerously seep into unwanted areas.

From Los Angeles Times • Oct. 4, 2025

Others use an espresso pot, which uses steam to drive water up through the grounds: the pot is a pressurized steam system, which is why it requires a safety valve.

From "The Invention of Science" by David Wootton