alarm clock

a clock with a bell or buzzer that can be set to sound at a particular time, as to awaken someone.

Origin of alarm clock

First recorded in 1690–1700

Kelley slept like a top, but woke at the first faint dawn, with the precision of an alarm-clock.

They of the High Trails |Hamlin Garland
Peter bent over his table, on which the wheels and springs of an alarm-clock were laid in careful rows.

The Jack-Knife Man |Ellis Parker Butler
Alarm-clock, one which can be set so as to ring loudly at a certain hour to wake from sleep or excite attention.

The New Gresham Encyclopedia. Vol. 1 Part 1 |Various
The alarm-clock does set on the shelf where it always sets all day long.

The Story of Opal |Opal Whiteley

Or attach a bell and let it be caused to ring at a certain point in the motionwhat was that but an alarm-clock?

Time Telling through the Ages |Harry Chase Brearley

alarm clock

a clock with a mechanism that sounds at a set time: used esp for waking a person up