Definition
The runway currently designated by air traffic control or, at non-towered airports, in use by pilots for takeoffs and landings based on wind and traffic conditions. Also referred to as the runway in use or duty runway.
Plain English
The runway that is being used right now for takeoffs and landings. At a tower-controlled airport, the controller decides which one. At a smaller airport with no tower, pilots choose based on the wind.
Context Anchor
You will hear or use this term when listening to airport information, talking with the tower, planning your taxi route, or checking which way traffic is moving at an airport.
Derivation
Active' comes from the Latin actus, meaning 'a doing' or 'in motion.' In aviation, the active runway is simply the one currently 'in action' — being used for traffic. The everyday meaning of active (in use, switched on) carries over cleanly here.
Why Pilots Care
Using the correct active runway prevents runway incursions and ensures the best possible wind conditions for safe takeoff and landing performance.
Intuition Check
Do not read “active” as meaning simply “available” or “open.” An active runway is the one being used or assigned for takeoffs and landings now.
Example Sentence 1
The tower advised the pilot that Runway 27 was the active runway and cleared him for takeoff.
Example Sentence 2
After the wind shifted, the active runway changed from runway 27 to runway 09.