1. 安全阀
A safety valve is a device which allows liquids or gases to escape from a machine when the pressure inside it becomes too great.
2. 发泄口;疏导情绪的办法
A safety valve is something that allows you to release strong feelings without hurting yourself or others.
1. a valve in a container in which pressure can build up (as a steam boiler)
it opens automatically when the pressure reaches a dangerous level