What does the term "airfoil" refer to?

The term "airfoil" specifically refers to any surface designed to produce lift when it interacts with airflow. This is fundamental in the field of aerodynamics, as airfoils are crucial for the performance and stability of aircraft. When air flows over an airfoil, the shape of the surface creates a pressure difference between the upper and lower sides, resulting in lift—a necessary force for an aircraft to rise and maintain flight.

In contrast, surfaces that generate thrust do not specifically relate to the term "airfoil," as thrust is created by engines or propellers. Components of landing gear do not produce lift; rather, they support the aircraft on the ground. Shapes used for flight control, like ailerons and elevators, may incorporate airfoil characteristics, but the term itself is more broadly associated with surfaces that generate lift in general flying conditions, making the description of an airfoil more precise in this context.