Definition
A portion of a route to be flown, as defined in an ICAO context, between two consecutive significant points. The significant points may be navigation aids, waypoints, fixes, intersections, or reporting points. A complete route is built up by joining route segments end to end.
Plain English
One leg of a flight route — the stretch from one named point on the chart to the next named point. String several of these legs together and you have the whole route.
Context Anchor
Seen in international flight planning, route descriptions, and aeronautical information that uses ICAO terms.
Derivation
‘Segment’ comes from the Latin ‘segmentum’, meaning a piece cut off from a larger whole. A route segment is literally one cut-off piece of the whole route — one leg between two named points.
Why Pilots Care
It defines the legs of a route for navigation, fuel planning, and compliance with ATC clearances.
Intuition Check
Do not read segment as just any tiny piece chosen at random. In this ICAO use, it means a route or part of a route normally flown continuously, with no intermediate stop.
Example Sentence 1
The pilot reported reaching the next waypoint and continued onto the following route segment toward the destination.
Example Sentence 2
ATC approved a direct clearance that shortened the next route segment by twenty miles.