Alarm – A call to arms in the face of danger or an enemy.
God used this word 10 times in Scripture, all to Israel in their Masoretic Text Old Testament, and all instances referring to a trumpet-call in alert to battle or defense.
The definition was extended in the 1700s to “any sound to warn of danger or to arouse”, as well as to the device that gives it. They weakened the word by adding ‘arouse’, like your morning alarm-clock, which has nothing to do with the original meaning.
In 1833 the definition was further extended to include “a state of fearful surprise”, “fright felt at the sudden realization of danger”, and “apprehension, unease”; these emotional responses have nothing to do with the original meaning.