Flasher/ˈflæʃər/ Definition 1 of 3Pro Tip 1/3Vehicle Signal Refers to a vehicle's warning lights, often used in emergencies or to signal turns. Hit the flasher; let's make a left here. Pro Tip 2/3Hazard Awareness Activating flashers alerts others to possible dangers on the road. Put the flashers on, we're broken down on the highway. Pro Tip 3/3Not Just Emergencies Used not only in emergencies but also sometimes when parked illegally or temporarily. I'll just put on the flashers while I unload these boxes.