Plain English Meaning

Navigation points that the pilot makes up and enters into the GPS or flight computer, instead of using the standard ones already printed on the charts.

Full Definition

Waypoints created by the pilot, rather than published on aeronautical charts, by entering specific latitude and longitude coordinates (or a bearing and distance from a known fix) into an area navigation system such as a GPS or FMS. The system stores these custom points so they can be used to build or modify a flight route.