"Reverse lights" refers to the bright lights at the back of a vehicle that turn on when the driver puts the car in reverse gear. They help the driver see what is behind them while backing up. Full definition
In some vehicles, the switch also monitors gear selection and reverse light feedback data for the vehicle's computer. (yourmechanic.com)
Featuring a smaller footprint in the rear corners, they take on a tinted appearance with the turn signals and reverse lights featuring clear lenses for a unique look. (topspeed.com)