fire alarm 
noun
A device making a loud noise that gives warning of a fire: a fire alarm went off and the building had to be evacuated...
- This time the ringing noise wasn't the fire alarm, but the dinner bell.
- That was when the idiots decided to test the fire alarm without the usual warning over the speakers.
- One girl bolted to the fire alarm and pulled it, setting the siren wailing and then sprinting for the door.
- departmentalization
- departmentalize
- departmentally
- Department of Agriculture
- Department of Homeland Security
- department store
- depart this life
- departure
- departure lounge
- depasturage
- depasture
- depauperate
- depend
- dependability
- dependable
- dependably
- dependant
- dependence
- dependency
- dependency culture
- dependent
- dependently
- dependent variable
- depending on
- depersonalisation