Plain English Meaning
How the air gets pushed downward behind the wing, and how that downward push changes depending on what the wing and flaps are doing.
Full Definition
The way air is deflected downward as it leaves the trailing edge of a wing or flap. The angle, strength, and pattern of this downward-flowing air change with airspeed, angle of attack, and flap setting, and these changes affect lift production, drag, and the airflow reaching the tail surfaces.
Context Anchor
Seen when learning how flap extension affects lift, drag, and pitch during , , and .