rotating warning light; patrol light
Abbreviation of 'patrol light'; a rotating or flashing warning light, especially the type used on police cars, ambulances, and other emergency vehicles. Often used in industrial or security contexts.
wasei-eigo (Japanese-coined English), from pat(rol) light
See also: パトカー
A rotating warning light is installed at the factory entrance.
When the patrol light rotates, it signals an emergency.