safety valve

1. N-COUNT A safety valve is a device which allows liquids or gases to escape from a machine when the pressure inside it becomes too great. 安全阀

Residents heard an enormous bang as a safety valve on the boiler failed. 当锅炉的一个安全阀失灵时，居民们听到了一声巨响。

2. N-COUNT A safety valve is something that allows you to release strong feelings without hurting yourself or others. 释放压力的手段

Crying is a natural safety valve. 哭泣是一种自然的释放压力的手段。