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.
- orientalia
- orientalism
- orientalist
- orientality
- orientalize
- Oriental Jew
- Oriental language
- Oriental Lowestoft
- orientally
- oriental plane
- oriental plane tree
- oriental poppy
- oriental rug
- oriental sore
- oriental topaz
- orientate
- orientation
- orientational
- orientationally
- orientation course
- orientation triad
- orientator
- orienteer
- orienteering
- Orient Express