Plain English Meaning
How far down the flaps are lowered, measured as an angle. A small angle means the flaps are barely lowered; a large angle means they are lowered a lot.
Full Definition
The angle, measured in degrees, to which the wing flaps are extended downward from their retracted position. Common settings include partial extensions (such as 10° or 20°) used for takeoff and initial approach, and larger extensions (such as 30° or 40°) used for final approach and landing. Greater deflection increases both lift and drag, lowers the stall speed, and steepens the descent path.
Context Anchor
Seen in takeoff, approach, and landing procedures when choosing the for the and .