What is the angle formed by the chord of an airfoil and the direction of the relative wind called?

The angle formed by the chord of an airfoil and the direction of the relative wind is referred to as the angle of attack. This angle is crucial in aerodynamics because it directly affects the lift generated by the airfoil. When the angle of attack increases, it typically results in increased lift, up to a certain point, known as the critical angle, beyond which lift can dramatically decrease, leading to a stall condition. Understanding the angle of attack is essential for pilots and engineers in designing and operating aircraft effectively, as it influences performance characteristics such as lift, drag, and overall aerodynamic efficiency.