1alarm 
/əˈlɑɚm/ noun
plural alarms /əˈlɑɚm/ noun 1 [count] a : a device that makes a loud sound as a warning or signal
▪ The alarm went off when he opened the door. ▪ a car alarm ▪ The whole town heard the alarm. ◊In figurative usage, when alarm bells are ringing people are worried about a possible problem or danger.
▪ His long absence from school set (the) alarm bells ringing and we finally called the police. — see also burglar alarm, false alarm, fire alarm, smoke alarm
b : alarm clock
▪ She set the alarm for six o'clock. ▪ The alarm went off at six o'clock. 2 [noncount] : a feeling of fear caused by a sudden sense of danger
▪ The rumors caused widespread alarm and concern. ▪ His parents have expressed alarm about/for his safety. ▪ The new developments are being viewed with alarm. ▪ She looked around in alarm when she heard the noise. ▪ There's no cause for alarm. [=there is no reason to be worried or afraid] synonyms 1fear 3 [count] : a warning of danger
▪ The dog's barking gave the alarm and the intruders were caught. ▪ A passerby saw the intruders and raised the alarm. ▪ They have ignored repeated alarms about the dangers of smoking. ▪ Economists have raised/sounded the alarm [=have warned people] about a possible recession. ▪ Economists have been raising/sounding alarms about a possible recession.
▪ The alarm went off when he opened the door. ▪ a car alarm ▪ The whole town heard the alarm. ◊In figurative usage, when alarm bells are ringing people are worried about a possible problem or danger.
▪ His long absence from school set (the) alarm bells ringing and we finally called the police. — see also burglar alarm, false alarm, fire alarm, smoke alarm
b : alarm clock
▪ She set the alarm for six o'clock. ▪ The alarm went off at six o'clock.
▪ The rumors caused widespread alarm and concern. ▪ His parents have expressed alarm about/for his safety. ▪ The new developments are being viewed with alarm. ▪ She looked around in alarm when she heard the noise. ▪ There's no cause for alarm. [=there is no reason to be worried or afraid] synonyms 1fear
▪ The dog's barking gave the alarm and the intruders were caught. ▪ A passerby saw the intruders and raised the alarm. ▪ They have ignored repeated alarms about the dangers of smoking. ▪ Economists have raised/sounded the alarm [=have warned people] about a possible recession. ▪ Economists have been raising/sounding alarms about a possible recession.
