Plain English Meaning
The data files inside a GPS or navigation unit that tell it where airports, runways, waypoints, and procedures are. Pilots can update these files themselves as part of preventive maintenance.
Full Definition
The electronic data files used by GPS receivers, flight management systems, and other onboard navigation equipment that contain information about airports, runways, navigation aids, airways, waypoints, instrument procedures, and airspace boundaries. These databases are issued by the manufacturer or a data provider and are updated on a regular cycle so that the navigation equipment reflects current published procedures and facilities.
Context Anchor
Seen when a or owner updates the in a or navigation unit as an allowed preventive maintenance .