Definition
That portion of flight operation between takeoff and the initial cruising altitude.
Plain English
The part of the flight after the wheels leave the runway and before the airplane levels off at its planned cruising altitude.
Context Anchor
Seen in departure procedures, takeoff briefings, aircraft performance planning, and air traffic control discussions after takeoff.
Derivation
“Climb” comes from an older English word meaning to go upward with effort. “Out” adds the idea of moving away from the starting point. Together, “climbout” points to the aircraft going up and away from the runway after takeoff.
Why Pilots Care
Determines obstacle clearance, noise-abatement compliance, and the moment for gear and flap retraction.
Intuition Check
Climbout does not mean every climb in flight. In this context, it means the climb after takeoff, from leaving the runway area until reaching the first cruise altitude.
Example Sentence 1
During climbout, the pilot retracted the flaps and reduced power to the climb setting.
Example Sentence 2
Tower asked us to report passing 500 feet on the climbout from runway 18.