What does airfoil mean?
An airfoil is any surface shaped so that air flowing over it produces useful aerodynamic force, most commonly lift. Wings are the classic example, but propeller blades, helicopter rotors, rudders, turbine blades, and even race-car spoilers all rely on airfoil principles. Engineers also speak of an airfoil as the particular two-dimensional cross-sectional profile — its curvature, thickness, and camber — that determines how air behaves around it. The term is standard in American English, while British usage favors the equivalent spelling aerofoil. Because it sits at the heart of aviation and fluid dynamics, airfoil carries a precise, technical connotation rather than a casual one, appearing chiefly in engineering literature, pilot training, and science education. Understanding the word opens the door to grasping how flight itself works: by shaping a surface so that pressure differences push it upward.
A structure with a curved surface, such as a wing, propeller blade, or rudder, designed to generate lift or other aerodynamic forces when moving through air.
"Each airfoil on the glider was polished to minimize drag."
In American English this is the standard term; British English uses aerofoil for the same concept.
The two-dimensional cross-sectional profile of such a lifting surface, defined by its chord, camber, and thickness distribution.
"The NACA 2412 airfoil remains popular among light aircraft designers."
This sense treats the airfoil as an abstract geometric shape rather than a physical component.
Standard pluralization applies; used when referring to multiple lifting surfaces or profiles.
"The aircraft's design required asymmetric airfoils on each wing."
Every airplane stays aloft because of the same curved shape found on propeller blades, race-car spoilers, and even some wind-turbine leaves — the humble airfoil.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of airfoil
Airfoil is a compound of 'air' and 'foil', the latter derived from Latin 'folium' meaning leaf. The same root gives us foliage, trefoil, and quatrefoil, reflecting the leaf-like shape of these surfaces. The term emerged in early twentieth-century aviation writing as engineers sought a precise vocabulary for lifting surfaces, with the British variant aerofoil developing alongside it.
How airfoil is actually used
Airfoil is standard in American technical and everyday usage; British writers typically prefer aerofoil. The word is neutral in register but appears most often in engineering, aviation, and physics contexts.
Easily confused with airfoil
Aerofoil is simply the British English spelling and name for the same object that Americans call an airfoil.