Definitionen
1.NounA valve set to open at a pressure below that at which a container holding a gas, vapour, etc. (such as a boiler or pressure cooker), would burst, thus reducing the pressure; a relief valve.
2.NounA valve set to close a container holding a gas or vapour to prevent excessive loss of pressure.
3.NounAny mechanism offering relief from physical or emotional pressure or tension.
4.NounA United States law, codified at 18 United States Code §3553(f), authorizing a judge to disregard mandatory minimum sentences for some criminals with few or no prior offenses.
5.VerbAlternative form of safety-valve.