2. A security device fitted to property; especially, a house or car, to make a warning sound if a break-in or theft is attempted.
3. A reference to an "alarm clock" or "alarm watch".
4. Fear caused by the perception of or the sudden sense of imminent danger: "Her parents have expressed alarm about her safety."
Historical Development
From the old French summons to battle a l'arme!, "to arms!" it seems a far cry to the modern alarm clock; yet, that is actually the scope of the word's development.
A l'arme! was first the call itself and then, in the form alarme, it became the name of this sudden summons.
The English alarm, which comes from this origin, first had the same meaning, but gradually broadened to indicate a warning signal of any kind of danger, and then the apparatus for giving this signal; such as, a fire bell.
It is interesting to also note that alarm has developed an additional meaning: the fear which results from a warning of danger.
Examples include the use by certain ant species of chemical defensive secretions that double as alarm pheromones.
An example is the odor trail system of lower termites, which is used to recruit colony members to the vicinity of intruders and breaks in the nest wall.
2. A component of an international network of alarm receivers actuated by a radio-frequency signal to indicate an international emergency.
2. Something that causes people to wrongly believe that a bad or dangerous thing is going to happen: "The report in the news that indicated the business was closing down was just another one of those false alarms."