Definition
The specific runway selected and used by an aircraft to perform its takeoff. At a controlled airport it is assigned by ATC; at a non-towered airport it is chosen by the pilot, normally based on wind direction, runway length, obstacles, and traffic.
Plain English
The runway you actually use to take off from on a given flight. It may not be the only runway at the airport, just the one being used for departures at that time.
Context Anchor
Used when discussing airport traffic patterns, departure flow, and which runway aircraft are using to leave the airport.
Why Pilots Care
Correct runway choice ensures adequate length, proper wind alignment, and safe separation from other traffic.
Intuition Check
Do not read this as any runway where takeoff is possible. Here it means the specific runway being used for departure at that time.
Example Sentence 1
The pilot taxied to the takeoff runway and held short until receiving clearance.
Example Sentence 2
After completing the pattern, the aircraft landed on the same runway it had used as the takeoff runway earlier.