Answer:
An airfoil is a blade that has an unequal cross section so that, as it passes through the air, the air it divides takes two paths of different length. The path of longer length has lower pressure on it than the path of shorter length. This causes lift, in the direction from higher pressure (shorter path) to lower pressure (longer path).
Wings, propellers, and turbine blades all have an airfoil cross section so that they can generate their own unique type of lift, or thrust, as the case may be. Angle of attack is part of this equation, but the airfoil is primary in making it all work effectively together.