alarm ( alarms plural & 3rd person present) ( alarming present participle) ( alarmed past tense & past participle )
1 n-uncount Alarm is a feeling of fear or anxiety that something unpleasant or dangerous might happen.
oft with/in N, N over/about n
The news was greeted with alarm by MPs...
2 verb If something alarms you, it makes you afraid or anxious that something unpleasant or dangerous might happen.
We could not see what had alarmed him. V n
3 n-count An alarm is an automatic device that warns you of danger, for example by ringing a bell.
He heard the alarm go off.
4 n-count An alarm is the same as an alarm clock.
6 If you say that something sets alarm bells ringing, you mean that it makes people feel worried or concerned about something.
alarm bells phrase N inflects
7 If you raise the alarm or sound the alarm, you warn people of danger.
raise/sound the alarm phrase V inflects His family raised the alarm when he had not come home by 9pm.
alarm clock ( alarm clocks plural ) An alarm clock is a clock that you can set to make a noise so that it wakes you up at a particular time. n-count
I set my alarm clock for 4.30.
burglar alarm ( burglar alarms plural ) A burglar alarm is an electric device that makes a bell ring loudly if someone tries to enter a building by force. n-count
car alarm ( car alarms plural ) A car alarm is a device in a car which makes a loud noise if anyone tries to break into the vehicle. n-count
He returned to the airport to find his car alarm going off.
false alarm ( false alarms plural ) When you think something dangerous is about to happen, but then discover that you were mistaken, you can say that it was a false alarm. n-count
...a bomb threat that turned out to be a false alarm.
fire alarm ( fire alarms plural ) A fire alarm is a device that makes a noise, for example with a bell, to warn people when there is a fire. n-count
smoke alarm ( smoke alarms plural ) , smoke detector A smoke alarm or a smoke detector is a device fixed to the ceiling of a room which makes a loud noise if there is smoke in the air, to warn people. n-count