'alarm' originates from Old French, specifically the word 'alarme', where 'a-' meant 'to' and 'larme' meant 'arms'.

'alarme' transformed into the Italian word 'all'arme', and eventually became the modern English word 'alarm' through Middle English.

Initially, it meant 'to arms' as a call to prepare for battle, but over time it evolved into its current meaning of 'to cause fear or concern'.