Which term describes the angle between the chord line of an airfoil and the relative wind?

The correct term that describes the angle between the chord line of an airfoil and the relative wind is the angle of attack (AoA). This concept is crucial in aerodynamics as it directly affects the lift generated by the airfoil. When the angle of attack increases, it increases the lift up to a certain point, known as the critical angle of attack. Beyond this point, the airflow may separate from the airfoil surface, leading to a stall.

Understanding angle of attack is vital for pilots, as it influences aircraft performance during various phases of flight, particularly during takeoff and landing. It is the fundamental measurement that pilots must consider to maintain control and ensure safety. The other terms—pitch angle, bank angle, and climb angle—refer to different aspects of aircraft orientation and maneuvering rather than the specific relationship between an airfoil's chord line and the incoming airflow.