What does the three upward arrows in a car mean?

[Myers]

Three upward arrows in a car represent the rear window defogger switch. Here is additional information: 1. Function: Pressing this button activates the heating wires in the rear window to generate heat. In winter, if the rear window is covered with snow, this feature can also help automatically remove the snow. 2. Cause of fogging: The difference between the interior and exterior temperatures of the car is too significant. When the outside temperature is lower than the inside temperature, the air inside the car cabin condenses upon cooling, forming fog on the inner side of the windshield. Conversely, when the inside temperature is lower than the outside temperature, water vapor in the atmosphere condenses upon cooling, forming fog on the outer side of the windshield.