Plain English Meaning

A wing cross-section whose underside is scooped or hollowed inward, like the inside of a spoon, instead of being flat or bulging outward.

Full Definition

An airfoil shape in which the lower surface curves inward (cups upward) rather than being flat or convex. This curvature increases lift at low airspeeds but produces high drag, so it is found mainly on early aircraft and on certain high-lift wing sections rather than on modern general aviation airfoils.

Context Anchor

Seen in airfoil design discussions when comparing different wing shapes and how their surfaces affect airflow and lift.

Derivation

Concave comes from the Latin concavus, meaning 'hollow' or 'arched inward.' It describes a surface that curves inward like the inside of a bowl, which is exactly what the lower surface of this type of airfoil does.