What is the meaning of alarm?

noun

• Fear resulting from the awareness of danger.
  • synonyms: dismay, consternation
• A device that signals the occurrence of some undesirable event.
  • synonyms: warning device, alarm system
• An automatic signal (usually a sound) warning of danger.
  • synonyms: alert, warning signal, alarum
• A clock that wakes a sleeper at some preset time.
  • synonyms: alarm clock

verb

• Fill with apprehension or alarm; cause to be unpleasantly surprised.
  • usage: "I was horrified at the thought of being late for my interview"; "The news of the executions horrified us"
  • synonyms: dismay, appal, appall, horrify
• Warn or arouse to a sense of danger or call to a state of preparedness.
  • usage: "The empty house alarmed him"; "We alerted the new neighbors to the high rate of burglaries"
  • synonyms: alert