What defines the "angle of attack" in aviation?

The angle of attack is defined specifically as the angle between the chord line of an aircraft's wing and the relative wind. This angle is crucial in aviation as it directly influences the lift generated by the wing. When the angle of attack increases, lift increases to a point, but when it becomes too steep, the wing can stall, causing a significant decrease in lift. Understanding this concept is vital for pilots, as it affects aircraft performance during various phases of flight, especially during takeoff, climb, and landing.

The other choices do not accurately define the angle of attack. The first option speaks to the overall orientation of the aircraft relative to the horizon, which can vary regardless of the wing's performance. The third option refers to the descent angle, which is unrelated to the wing's aerodynamics. Lastly, the fourth option addresses the angle of climb, which also does not encompass the specific aerodynamic relationship between the wing's chord line and the relative wind necessary for defining angle of attack.