Definition
The greatest angle of attack at which a wing can produce lift before airflow over its upper surface separates and the wing stalls. Beyond this angle, lift drops sharply regardless of airspeed, attitude, or aircraft weight. Often referred to as the critical angle of attack.
Plain English
The steepest angle the wing can meet the oncoming air before it stops flying and starts stalling. Tilt the wing any more than that into the wind and lift collapses.
Context Anchor
Seen in lift, stall, slow flight, and landing discussions, especially when explaining why an airplane can stall at many different speeds or attitudes.
Derivation
Maximum comes from Latin maximus, meaning greatest. Angle of attack describes the angle at which the wing 'attacks' or meets the oncoming air. So 'maximum AOA' is simply the greatest angle the wing can meet the air before it can no longer keep flying.
Why Pilots Care
Reaching or exceeding this angle produces an aerodynamic stall; recognizing the approach to it is essential for maintaining control during slow flight and turns.
Analogy
Think of holding your hand out of a car window and slowly tilting it upward. At first it pushes up more strongly, but if you tilt it too far, the air no longer flows smoothly over it and the lift-like push weakens.
Grounding Statement
Picture the wing being raised into the oncoming air until it reaches the last usable angle before the airflow stops staying smooth over the top of the wing.
Intuition Check
Maximum AOA does not mean the highest nose-up attitude or the steepest climb. It means the greatest angle between the wing and the oncoming air, and it can be reached in many different airplane attitudes.
Example Sentence 1
The instructor demonstrated how the wing stalled the moment they exceeded the maximum AOA, even though airspeed was well above the published stall speed.
Example Sentence 2
The pilot reduced power and increased back pressure until the wing reached maximum AOA, then lowered the nose to recover.