Definition
A published route that connects the en route structure to an instrument approach procedure, providing a charted path from a feeder fix or initial approach fix into the approach itself. Terminal routes are depicted on instrument approach charts and define the course, distance, and minimum altitude a pilot must fly to transition from cruise navigation to the final approach segment.
Plain English
It is the marked path that links the route you fly on the way to an airport with the start of the instrument approach into that airport. It tells you which way to go, how far, and how low you can be while doing it.
Context Anchor
Seen on instrument procedure charts and IFR en route charts when an aircraft is moving between the en route system and the airport-area approach environment.
Derivation
Terminal here means the end portion of a flight, the part near the airport where arrival and approach happen. The word comes from the Latin terminus, meaning end or boundary. So a terminal route is simply a route used in the end stage of the flight, just before the approach.
Why Pilots Care
Flying the terminal route correctly keeps the aircraft on a charted, obstacle-protected path with a guaranteed minimum altitude. Skipping it or improvising can put the aircraft outside protected airspace and below safe terrain clearance.
Intuition Check
Do not read terminal route as a route to the airport passenger terminal. Here, terminal means the airport-area part of the instrument flight system.
Example Sentence 1
After being cleared for the approach, the pilot flew the terminal route from the feeder fix to the initial approach fix at the charted minimum altitude.
Example Sentence 2
Terminal routes are used to transition smoothly from en route navigation onto the beginning of the instrument approach procedure.