alarum

Etymology
From, from , from.

Noun

 * 1)  A danger signal or warning.
 * 2) A call to arms.
 * 1) A call to arms.
 * 1) A call to arms.
 * 1) A call to arms.

Verb

 * 1)  To sound alarums, to sound an alarm.

Usage notes

 * Alarum is an old spelling of (as a noun or a verb), which has stayed around as a deliberate archaism. Possibly it is retained because of its use in Shakespeare's plays.