Plain English Meaning
A way to fly an instrument approach to a runway by following GPS-defined points in space, instead of following signals from radio beacons on the ground.
Full Definition
An instrument approach procedure that uses Area Navigation (RNAV) based on Global Positioning System (GPS) signals to provide lateral, and in many cases vertical, guidance to a runway or landing area. The aircraft's GPS receiver computes its position from satellite signals and follows a sequence of named waypoints published on the approach chart, allowing the pilot to fly the approach without reference to ground-based navigation aids such as VORs or localizers.