noun
red light; red warning light
Typically refers to the red rotating or flashing light on emergency vehicles such as police cars, ambulances, and fire trucks. Also used for similar warning lights in other contexts.
パトカーの赤色灯が回っている。
The police car's red light is spinning.
救急車の赤色灯が見えたら道を
If you see the red light of an ambulance, please give way.