An airfoil is the shape of a wing or rotor blade as seen in cross-section.

An airfoil shaped body moved through a fluid produces a force perpendicular to the motion called lift.

A wing is designed for flight. It has a special shape called an airfoil. Airfoil shapes can be found on wings, fans and propellers. The airfoil shape provides a lifting force when air flows around it. An airfoil has a thicker; rounded leading edge (front end) and a very thin trailing edge (or back end). In between the leading and trailing edge it is curved both on the top and bottom surfaces. The top surface usually has a greater curve (or hump) than the bottom surface. When a surface is curved we say it has camber.

An airfoil takes advantage of Bernoulli's Principle. Since the top surface of the wing has more camber than the bottom surface, the air flows faster over the top of the wing than it does underneath. This means that there is less air pressure above the wing than there is beneath the wing. The difference in air pressure above and below the wing causes lift.