English: * The angle of attack is measured relative to freestream velocity (measured far ahead), not local relative velocity (which varies both in direction and magnitude in the vicinity of the airfoil) ;

• The chord line is a straight line going from the leading edge (point of minimum radius) to the trailing edge;

• The mean camber line (or simply "camber line") is constituted by the midpoints of all airfoil cross-section segments perpendicular to the chord.

Note that the thickness can be defined in several ways (see File:Airfoil thickness definition.svg). The so-called "British convention" is used here.