Plain English Meaning
The on-board programs that take the raw navigation data stored in the aircraft and turn it into something useful for the pilot — like showing a route, guiding an approach, or warning about terrain.
Full Definition
Software programs and systems used in aircraft avionics that read data from a navigation database to perform flight-related functions, such as flight planning, route guidance, terrain awareness, and approach procedures.
Context Anchor
Seen in discussions of airborne navigation databases, where stored aviation information is used by and tools.