Plain English Meaning

The angle at which the wing meets the oncoming air. Tilt the wing up too steeply into the air and it stops producing lift — that is a stall.

Full Definition

The angle between the chord line of an airfoil and the relative wind — that is, the direction the air is actually meeting the wing. As angle of attack increases, lift increases up to a critical value; beyond that critical angle, the airflow separates from the wing and the wing stalls.

Context Anchor

Seen in stall awareness, slow flight, turns, takeoff, landing, and any discussion of why a stalls.