alarum Meaning, Definition & Usage

  1. noun an automatic signal (usually a sound) warning of danger
    warning signal; alarm; alert.

WordNet

A*lar"um noun
Etymology
OE. alarom, the same word as alarm, n.
Definitions
  1. See Alarm. Now Poetic ✍ The variant form alarum is now commonly restricted to an alarm signal or the mechanism to sound an alarm (as in an alarm clock.)

Webster 1913