Final answer:
The FLAP OVRD GRND PROX switch light is a cockpit control that allows pilots to prevent nuisance warnings from the Ground Proximity Warning System related to flap settings when an aircraft is on the ground.
Step-by-step explanation:
The FLAP OVRD GRND PROX switchlight on an airplane is related to the aircraft's Ground Proximity Warning System (GPWS). This system is designed to alert pilots if their aircraft is in immediate danger of flying into the ground or an obstacle. The FLAP OVRD (flap override) feature allows pilots to inhibit nuisance warnings that might otherwise occur during certain operations where the aircraft's configuration (for example, the position of the flaps) might generate false warnings.
Essentially, it temporarily overrides certain functions of the GPWS related to the flap settings when the aircraft is on the ground to prevent false alarms. This is an important safety feature, particularly when taxiing or during takeoff and landing preparations.