safety_valve
1. [ noun ] 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
Synonyms: escape_valve escape_cock escape relief_valve
Related terms: regulator valve
Similar spelling:   safety_fuse
  safety_bike
  safety_belt
  safety_pin
  safety_feature
  safety_bolt
  safety_bicycle
  safety_blitz