WordNet
n. a whistle at a factory that is sounded to announce times for starting or stopping work
Usage examples of "factory whistle".
How to pre-adapt children for a new world--a world of repetitive indoor toil, smoke, noise, machines, crowded living conditions, collective discipline, a world in which time was to be regulated not by the cycle of sun and moon, but by the factory whistle and the clock.
Susi's mom, who supports the Girl Scouts and never sends the Cancer Society lady away empty-handed, shrieks like a factory whistle at quitting time.
It was the insane shriek of a factory whistle, but much louder and strangely organic, as though from a living throat, not a machine, and it took the starch right out of his legs.
The sound was a high-pitched, piercing shriek, like that of a factory whistle, but it came from a living throat.