Definition
The phase of flight in which an airplane transitions from ground operation to flight, beginning with the application of takeoff power and ending when the airplane has lifted off the runway, established a positive rate of climb, and reached a safe maneuvering altitude.
Plain English
The act of getting the airplane off the ground and safely into the air, from the moment you push the power up to the point you are climbing away cleanly.
Context Anchor
Seen in basic flight training whenever a flight begins, and in handbook discussions about how the four basic flight skills are combined to get the airplane airborne.
Derivation
A plain compound of 'take' and 'off' — the airplane 'takes itself off' the ground. The aviation use dates to the early 1900s and replaced earlier nautical-style terms.
Why Pilots Care
Correct takeoff technique ensures the aircraft reaches safe flying speed, clears obstacles, and avoids runway overrun or loss of control.
Intuition Check
Takeoff does not mean only the instant the wheels leave the ground. In pilot training, it usually means the whole action of accelerating, leaving the surface, and starting the climb.
Example Sentence 1
After completing the before-takeoff checklist, the pilot lined up on the runway and began the takeoff.
Example Sentence 2
During the takeoff roll the airplane must reach rotation speed before the nose is raised.