Plain English Meaning
A screen in the cockpit that shows where the airplane is on a map right now, with the map sliding underneath the airplane symbol as you fly.
Full Definition
An electronic cockpit display that shows the aircraft's current position on a chart-like graphic in real time, with the map continuously updating around a fixed aircraft symbol as the airplane moves. The position is derived from GPS or other navigation sources, and the display typically shows terrain, airports, airspace boundaries, navaids, and the planned route.
Context Anchor
Seen on many modern flight displays, GPS units, and tablet navigation apps used in the cockpit.