Definition
A taxi maneuver in which an aircraft moves on a runway in the opposite direction of normal landing or takeoff traffic flow, typically used to reposition an aircraft to the threshold for departure or to exit the runway after landing when no parallel taxiway is available. Back-taxi operations require ATC clearance at controlled airports.
Plain English
Driving an aircraft along the runway in the wrong direction — opposite to the way planes are landing or taking off — usually to get back to the start of the runway before takeoff, or to reach a turnoff after landing.
Context Anchor
You may hear this in taxi instructions at airports with limited taxiways, especially when an aircraft needs to use part of the runway to reach the takeoff end.
Derivation
Back' meaning reverse direction, plus 'taxi' (the standard aviation term for an aircraft moving under its own power on the ground). The compound simply means taxiing backward along the traffic flow — not literally reversing, but going against the normal direction of use.
Why Pilots Care
Allows safe repositioning on the runway at airports without full taxiway systems, but requires explicit clearance and constant vigilance for landing or departing traffic.
Intuition Check
Back-taxi does not mean the airplane is moving backward. It means the airplane is taxiing forward along the runway, but opposite the normal runway traffic direction.
Example Sentence 1
Cleared to back-taxi runway 27, hold short of runway 18.
Example Sentence 2
After landing long, the pilot received clearance to back-taxi to the nearest taxiway exit.