the.com/alarm clock

means A clock fitted with a device that sounds a signal at a preset time, usually to wake someone up.

from Traces back to the Italian 'all'arme' — 'to arms!' — the cry raised to summon soldiers to sudden defense. That urgency carried into English 'alarm,' meaning a call to danger or vigilance, centuries before it got bolted onto a clock. The mechanical alarm clock itself emerged in the 1800s, finally giving every ordinary person their own tiny, personal call to arms — against the snooze button.