a burglar alarm, fire alarm, or the like, that is activated silently and transmits a warning signal, usually by telephone.
What Does ⏰ Alarm Clock Emoji Mean?The alarm clock emoji depicts an old fashioned alarm clock, sitting on two short legs with two clangers (yup, that's a technical term) perched on top.
Origin of still alarm
An Americanism dating back to 1870–75
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019